I'm (re)writing this review in the hope that it may help some of the folks out there who have struggled with the "Printer is offline" error message in Windows without much success. One post I ran across in an online support group said he had tried three different 7740 units and all gave the same error message and that HP tech support was useless. I'm sure that's probably true. I struggled with the same issue after a new wireless installation and it came close to driving me nuts. I seriously thought about sending the printer back, but the fact that the online poster had tried three different units gave me pause. The likelihood of three identical machines all being hardware defective in the same exact way is pretty darn small.If you're lucky, the problem may be as simple as unchecking the "Use printer offline" box. Go to "Control Panel," "Devices and Printers," right click the HP 7740, click "See what's printing," then click "Printers" at the top of the next window and uncheck "Use Printer Offline." But if you're unlucky, like I was, "Use Printer Offline" won't be checked anyway. Don't panic. While I offer no guarantees that what I've written below will help and take no responsibility for any damage you may do to your setup trying to follow my advice, it may again be helpful for some people's situations, even for folks with a different printer.Let’s think about what “Printer Offline” really means. As many have said it doesn’t mean the printer is “off” or won’t print a test page from the control screen. What it means is that Windows can’t find it.There are at least two possible reasons for this. One is that you have a driver conflict with a different printer. You may not even think you have another printer installed, but because of how Windows operates you may.Another cause may be that Windows can’t find your printer where it thinks it should be because of how your router is assigning your printer’s wireless (IP) address. I suspect this is an even more common problem but has a fairly straightforward though involved solution.The LEAST likely cause is a hardware defect. As the example above shows, the likelihood that three identical units are all defective in the same way is practically nil. It is almost always a problem with Windows “finding” the printer, that is to say, software communication issues, not with the printer itself.OK – apologies for the length of this in advance.In the case of a driver conflict – which I had, unbeknownst to me – I found the conflict when I right clicked on "Printer Properties" in "Devices and Printers (in Control Panel)," and then clicked the "Ports" tab. There to my surprise was an HP driver installed for the HP Envy, even though I'd never had the Envy connected to this computer. (It was left over from cloning the boot drive from another OS.) The 7740 was listed as the default printer, but the Envy driver had the TCP/IP port and was “online.” The Envy seemed to be confusing the OS into thinking that the Envy should be online and the 7740 shouldn't be.The immediate solution there was to delete ALL the printer drivers (including the 7740) from the machine. (You can't delete MS XPS or Adobe PDF but that's OK.) You can try just deleting every printer listed in "Devices and Printers" by right clicking them and choosing "Remove Device," but you may need to use an uninstall program or go into the Windows Registry - which is NOT for novices. (Basically DON'T if you don't know exactly what you're doing and aren't prepared to reinstall your whole OS. Fair warning!) Deleting drivers isn't always easy, but again, the error message is probably not caused by a problem with the 7740 hardware itself. As other sites describe, I then manually reset the 7740 unit by unplugging it while it was still powered on, waiting 60 seconds, and plugging it in again. It powered on automatically.Once I did that, I reinstalled the 7740 drivers MANUALLY in "Devices and Printers" using the "Add Printer" button. (It's usually the best way to do a wireless printer install anyway.) The OS found the 7740 using the TCP/IP port (the TCP/IP connection - always best), and it all worked fine – for a time.That’s when I discovered the second likely cause for the “Printer Offline” error message. Even though I no longer had driver conflicts, Windows still often lost track of the wireless address (the IP address) of the 7740. Why would Windows do that? Let me explain.Modern routers assign IP addresses to any device that connects to your wireless network automatically by a protocol called DCHP. Before DCHP, routers assigned addresses the way you get a social security number: each person gets her own unique number and no one else has it. Good enough. But because there can be so many devices connected to a home network, and also because as devices turn off and on they disconnect from and then reconnect to the network, DCHP will REUSE addresses from a disconnected device for a NEW device that connects (or an old device that reconnects), even if a device that reconnects had a different address before. Or it may get an entirely new address. Whatever. This means that when your printer “goes to sleep” to save energy and thus disconnects from the network, when you go to wake it up to print something later, the DCHP router will give it a DIFFERENT IP address from the one it first had, but Windows, bless it, will still try to find the printer at its old IP address. And if it can’t, which it often can’t, Windows will conclude that your printer is “offline” and refuse your new print job. It’s the equivalent of the Post Office “Moved. No Forwarding Address.” (DCHP is fine for most devices but for whatever reason doesn’t play well with many printers.)Again, this isn’t the printer’s fault, though it is to some degree the manufacturer’s fault, since they don’t tell you how hard it can be to make a solid wifi connection for a printer to a network. “Just put your install CD in your CD drive and…” Yeah no.So how to fix? Well it can be intense but it’s been working for me for several days now, fingers crossed.First, go to your router’s admin program. It will have an address like 192.168.0.1 (Read the router manual.) Type the address into your browser (the periods are important). You’ll need the userid and password for the router, something like “admin” “admin1” depending on model. Check the manual.Go into your router IP address settings – maybe on a tab like "LAN settings" (manual will show). This tab will show the router’s starting IP address setting – the numerically lowest address the router will assign to a device – and the highest IP address setting – the highest numerical address a router will assign. These will typically be something like 192.168.0.2 and 192.168.0.255. See photo.Change the last three digits for the highest setting to any lower number – for simplicity’s sake say 250.Apply the change. Leave the router admin window open for now.Go to your printer’s settings screen on the 7740 and locate the printer IP address, again something like 192.168.0.xxx. Type that into a new window in your browser too.You’ll then get the 7740 internal settings screen in your browser window. Go to Networking, Wireless, and IPv4 addresses. Deselect “Automatic IP” or “DCHP” and select “Manual IP.” In the actual address space type in the first three segments of the numerical sequence you typed above, and then “251 (or 252 or 3 or 4)” for the last segment. See photo. Hit Apply/Save. Also, on the “Network” tab choose “Network Protocols.” “Check IPV4 Only” and “Apply.”Ok. A few more steps. Go back to your router window to the LAN settings page. If you’re lucky, your router will have a setting that lets you MANUALLY assign an IP address to a device. See photo. (Can’t help you here if you’re not.) Get your MAC address for your printer from the printer settings “General Summary” page. See photo. Type that address into the “New Device” or whatever space on your router manual assignment page. The IP address should come up automatically. See photo. Exit your router setup.Go back to your 7740 settings. Go to “Network” “Advanced Settings” “Microsoft Web Services.” Uncheck everything. See photo.Go back to HP 7740 in “Devices and Printers” and delete it by right clicking “Remove device.”Next go to “Add Printer” on the “Devices and Printer” page on the upper bar, and choose “Add network printer.” The wizard will search and should find the 7740 at the IP address you just assigned it, 192.168.0.251 or you can enter it manually. (Remember, use the first three segments that your printer settings panel says, not this example.)Go with “Use the current driver” or you may need to select the manufacturer and then the specific printer. No worries.When you get to “Print Test Page,” click it. Your page should print, your printer now has a PERMANENT IP address so Windows should never lose track of it again and thus should never say it is “Offline.”The reason this is so involved is why printer manufacturers don’t want to tell you to do all this to install a wifi printer. And in many cases they don’t need to. But in other cases they do.This is also called “setting a static IP address.” There are simpler procedures on the web but they didn’t work for me. “Howtogeek.com” and “linerarthoughts.co.uk” are the main sources if you run into difficulties. Again, when so many people are having the same problem it usually isn’t the hardware. Hope this helps. Please comment if you find mistakes. Best of luck!