Both Oblivion and Fallout 3 on my PC have this weird sound bug. The problem is there is no background music. With Oblivion it is just gone, and nothing can be heard. With Fallout 3, however, I get this squeaking and chirping noise in place of the BGM. Like it's trying to play, but it just sounds like a skipping record or disc.

Bethesda support told me, about a year ago, it was my OS. They said that both games were not made for Windows 7 64bit, and they could not help me. Now, with Skyrim using a new engine, what are the chances this bug will not be apparent? Skyrim is using a new engine, right? However, I read it will not fully support a 64bit OS, so I'm not sure what to do.

Also, I've tried every fix I could think of or find on Google. From uninstalling CODEC packs, to reinstalling CODEC packs, uninstalling MoBo sound drivers, and even editing existing CODEC settings, but nothing works. The only thing I've not tried doing is just formatting my PC which I would like to avoid just for two games.

I would also like to note I even tried the fixes listed on this page as well.
http://www.uesp.net/wiki/Oblivion:Technical_Support#No_music

I know my system can run the game just fine, but I would hate to spend sixty dollars just to experience such an annoyance again. Some people have told me to get a sound card but I'm not quite sure how that will work.

Thanks in advance.