Well, okay.
When you install Windows, you either format or upgrade.
It usually decimates your drivers.
If your computer has CD's that came with it for drivers, then use those. For example, mine does. I have one for my Nvidia graphics card which allows it to work.
If not, then you probably got a pre-baked system from a store. What is the 915gm?
I'll need specific info here.
Assuming your drivers are all gone, we need:
-Graphics Card Make and Model
-Sound Card Make and Model
-Printer (if you have one) Make and Model.
The rest ought to take care of itself, for now.
I am assuming you have internet, as we're chatting.
Windows Update is okay for finding a few choice drivers, but, wholly, it doesn't do too good of a job sometimes. So likely you'll have to go to individual vendor's websites and get your drivers from there.