Until The Partitions Read "Windows 7 Cannot Be Installed To This Disk?

Wasn't sure whether I should put this in WIndows 8 discussion or WIndows 7, butconsidering it's going from eight to seven, it would be more relevant to go into seven, especially since I think I've cleared eight almost entirely from the machine, but I'll explain that later. Also excuse my English right now, I've been awake for.... well longer than twenty four hours, so my mind is a bit scrambled and I'd just like the peace of mind of having this up here before I head off to sleep.
 
Well anyways, it feels a bit impolite to show up with nothing but a problem to present, so I'll make it a point to at least present myself. I've found this site many a times when dealing with viruses and other such problems through Google search results. I had noted what a great site this was, from the generally friendly people to the fact that anytime I would find a thread here pertaining to my problem, it would either be solved here or I would be pushed pretty drastically in the right direction. This was always my "go to" place if I ever really had a problem I needed worked out that I couldn't figure out myself. As you've already guessed, that's why I'm here in the first place.

So to sum it up shortly my friend had asked me to revert his new Windows 8 laptop back to the Windows 7 interface, me knowing more than him enough for him to trust me with it.However, I'm no IT, I'm just someone who happens to have picked up knowlege over the years from dealing with my own problems and such. It didn't seem to be an IT job, so I felt it was within my league. First thing I do is fish out the WIndows 7 installation disk. After fiddling with Windows 8 for a while trying to figure out how to boot from disk (is it just me or did Windows 8 overcomplicate that way too much?), I managed to get to the boot order settings. However, the CD drive was entirely gone from there. I assumed it was something involving the new laptop and not having the proper drivers installed or something, so I followed through a guide and got it all onto a flash drive so I could boot from that instead of dealing with the phantom CD drive this laptop seemed to have.

One step done, I felt I was heading in the right direction. However, things began taking a turn for the worst when for whatever reason it wouldn't load from the flash drive. It was recognized at least, and there was a noticable pause at start up where the light on the flash drive began blinking frantically as if it's trying to do something, but then it just skipped over to the regular Windows 8 log on screen. I tried just about all the basic troublshooting steps under the sun here, different USB slots, formatting the drive and cleanly setting it up to be a boot disk a few more times, changing the boot order again, etc. I started poking around online for solutions, and, well my fatigued brain is having a bit of a hard time remembering if I did anything other than this, but if I did I know I wasn't just poking at random switches and such in the BIOS, even I realize the danger of that and all, and if there was something other than this I know that it was only one other thing, which I suspect is what actually made it work. Now for the big delivery, MISTAKE #1 : There was a setting somewhere in there that I changed, I'm guessing I misread what was said online, but I changed it from UEFI, to CSM.

Saved changes and restarted. Booted fine from the flash drive and I was pretty happy, until the partitions read "Windows cannot be installed to this disk, The selected disk is of the GPT partition style" Now here's where I started to panic. So much so I engagued into big mistake #2. I deleted the partition containing Windows 8 and tried to make a new one for 7. That would work right? It would build the next partition to fit what Windows 7 needs to install right? Not the case, still remained with the GPT error on the newly made partition. So here I am, with a Windows 7 that refuses to install, and when I load it normally I get this wonderful screen[CODE]