Well here's the simplest form I can give it;

My DVD-RW simply doesn't work 100% since I upgraded to W7 Ultimate, no idea why it's just turned into a massive moron, it reads only certain Game discs, and it won't ever pick up a normal disc with files on, Films/Music/Anything, it's getting quiet annoying now, my dads looked at it, and he's being around PCS for the last 30 years and he can't figure it out. My brothers also looked but to no prevail we found an answer.

If you need any information tell me I'll gladly provide it.

Another note, it's a custom built PC

It has either coincidentally failed with the Windows 7 install or you have some sort of SATA/PATA corruption going on (possibly due to motherboard chipset drivers not being installed).

I would test it in another PC if possible. They are so cheap these days that if it is broken I would just buy a new one.

Assuming the drive is recognized in both Device manager and Disk manager, your drive may require more power. If the drive cannot achieve a certain RPM (commonly characterized by 2Xspeed, 8Xspeed, 16Xspeed etc...) it can cause disks requiring a certain read speed to become, you guessed it, unreadable. This guy had similar problem --> http://www.sevenforums.com/hardware-devices/40477-dvd-drive-not-reading-disks.html

So maybe a new PSU is in order? One with a large amount of power supplied to the +12V rail --> "The most important voltage rail in a power supply is the +12V rail. This voltage rail supplies power to the most demanding components including the processor, drives, cooling fans and graphics cards. All of these items draw a lot of current and as a result you want to make sure that you purchase a unit that supplies enough power to the +12V rail."

If its the case that the drive is unrecognized by Win 7 then you could try this solution --> http://www.windows7news.com/2009/01/15/windows-7-not-recognizing-dvd-drive/