Weird problem with Windows 7

I tried looking for help but there's no way to search for the problem I'm having, I tried. I've had 7 before and everything was fine but this time, something's weird.

I just recently installed Windows 7 x64 Ultimate Edition and the problem's are that when I play a video file (doesn't matter what player) and try to install a game, my sound for my whole system gets screwy (it starts making severely distorted sounds) and I lose access to all my files until reboot. If I try to access a file it says "not found" and if I try to install something it says "drive not found".

If I play a video file and nothing else, it's fine.

When I reboot everything is fine. I did an update earlier today with everything and it still happens.

Any clues?

Thanks for the help, I'm about to give that a shot. I just tried to install another game and it worked without a hitch, maybe it was that game that is corrupt or something it only does it when I try to install that game, anything else works fine.

So weird lol but thank you again for your help, I'll make sure to jot that down and save it for future use.

Uninstall your sound driver, restart to let Windows reinstall it.

As suggested, update all of your drivers (especially chipset, video, sound) from the latest on your computer/device maker's Support Download's webpage.

Make sure no drivers are cued in optional Windows Updates.

Run sfc /scannow to check integrity of all system files.

Finally, as a last resort before reinstall run a Repair Install