Vista going crazy

I put the entire World of Warcraft program folder on my external hard drive and dragged+dropped that folder onto another PC's hard drive, in the program files folder.

It ran just fine, but the framerate was very low for the computer's specs, so I updated the driver for the video card.

After I updated the driver, the system started going painfully slow, and the little loading disk that appears next to the cursor in Vista pops up every few seconds and the computer is constantly beeping at me for seemingly no reason.

I figured it might have been a plug+play problem since i removed my external hard drive without "safely removing" it, but I can find no indication of this to actually be the problem.

My dad's pretty mad at me for this, so if you can offer any help at all, I would greatly appreciate it.