How to safely revert from Windows 8 to Windows 7?

Long story short, I need to revert back to Windows 7 from Windows 8 on an Alienware M17x-R3. Is it possible to do this without affecting my files, pictures, video, etc? Thanks for any help you can give me. For the full story, read on. For a shorter version of the long story, skip to the last couple of paragraphs. Okay I got my Alienware M17x-R3 back in summer 2011 with Windows 7. Fast forward to October 2012 and I got Windows 8 on day one. Don't get me wrong, I love Windows 8 and am a proud Surface owner, but there are just too many Windows 8/Alienware compatibility issues for me to handle anymore and I think the best course of action is to go back to Windows 7. Here are the issues: To begin with, ever since I installed Windows 8, the laptop does not properly go into Sleep mode anymore. This mainly means that I can never shut the lid of the laptop. If I do, it goes into sleep mode, but then when the computer wakes back up, the screen actually never powers back on. This happens every time and the only way out of it is to do a hard shut down and turn the computer back on. So now my computer may run at weeks or maybe months at a time. I'll occasionally restart it to refresh some things. I contacted Microsoft about this issue back around winter 2012 and they said there were some problems specifically because this Alienware laptop was not compatible with Windows 8. But I thought heck I can live without ever closing it or putting it in sleep mode. I use it as a desktop anyway and it's always plugged in. Next issue is the sound. Since Windows 8, the Alienware has inexplicably lost all 5.1 surround sound capability through HDMI out and I have never been able to fix it. It only outputs stereo. Again, currently this isn't a big problem as it's only ever output to an HDTV with stereo sound, but I would like to have surround sound if I get a theater system in the future. About a year ago, I had to boot the computer straight from the Windows 8 OS cd. This was completely my fault however. I shut it down during a disk check. Don't ever do that. I got the Windows 8 frowns face screen saying it messed up some configuration files and was then completely unable to find its boot path. Thankfully I was able to boot it from the CD and do a system restore to a previous point from two weeks earlier, and everything was fine. Again, this was my fault and I don't think it has to do with Windows 8/Alienware compatibility issues, but I figured I'd include it anyway. Now for some more recent problems. I've noticed over the past few months, Windows 8 functionality has slowly degraded to the point where the Windows Store and OneNote app (the only two I currently know of) will not open at all under any circumstances. As soon as I click the app, the splash screen appears then disappears and I'm back at the Start screen. This has prevented me from ever upgrading to Windows 8.1, even from the banner that comes across when I restart asking if I want to upgrade. I click open store to upgrade and it immediately closes it. Also, if I go to PC Settings at the bottom of the right pull-in banner (where the search, wifi, brightness, etc are), that app will open and function, but freezes after I click any one of about half of the options there. And finally, most recently is the biggest problem. I have a 2TB external hard drive plugged into my computer all the time that I am constantly using. For two years I have used this hard drive quickly and easily without issue. Over the course of about the last 24 hours, the speed of Windows being able to access this drive has grinded to a halt. I was copying a 1 GB file from the external hard drive to the desktop, a process that would normally take 15-30 seconds, and this time took 15 minutes. The hard drive would copy at about 4-6MB/s for maybe 1 or 2 seconds and then it flatlined and would stop transferring anything for about 1-2 minutes before picking back up again momentarily. I restarted the computer twice, determined the issue was not with the external hard drive because it works properly with my Surface, and had two failed attempts at a PC Refresh (it simply restarted and at the desktop said "There was a problem refreshing your PC. No changes were made). So I decided it was time to try a System Restore. Until I went to try it and it told me that no restore points existed for this computer. I can not fathom why this is the case as I have performed a System Restore three or four times on this computer, the most recent being last summer. The computer now doesn't seem to recognize the external drive. It beeps when inserting and removing it from the USB port as it should, but when I try to navigate to it, it gives one of those empty windows with the green loading bar at the top that goes across for 15 minutes and always ultimately fails. Once I got "this location does not exist" and another time I got a "semaphore timeout period has expired" error which I've never seen or even heard of before. It seems I've run out of options, and frankly I'm tired of these little compatibility errors popping up. Now that it no longer recognizes my drive and I can't restore, this is a big problem, and I feel my best choice is to revert to Windows 7, very preferably without having to completely reformat the computer to factory settings. I have a backup of about 90-95% of my irreplaceable things like pictures, documents, and videos on my external hard drive. But I would love to avoid the massive ordeal of reinstalling replaceable things like programs and Steam games, copying back over the hundreds of gigabytes of backed up stuff, and having to get all of the computers settings right. Plus there's the factor of the most recent things not being backed up yet (although I may be able to back those up to another drive if absolutely necessary and given that the computer will recognize a different drive). So, sorry for making such a ridiculously long post, but I would very much appreciate any help and advice. Thanks you guys.