yeah, there's no telling what the computer place did
they could have reinstalled windows without reformatting the computer, which is a no-no because it causes huge fragmentations, and allows the computer to automatically find the old drivers on the hard disk, which is bad
they could have also simply repaired windows, which simply overwrites the configuration files, which leaves all of your old applications on the hard drive, even though they're not even installed anymore
do yourself a favor, and backup your mp3's and stuff to an external hard drive, completely reformat your drive, and then do a FRESH install.
all you need is an internet connection, and you'll be able to find all your drivers online, and then simply copy all your mp3's and movies back onto your computer, and you'll be good to go, with up-to-date drivers, and 0 fragments, you'll be faster than evar.