Vista - Startup repair problems

Someone please help an amateur like me.

I've just purchased a quite powerful cpu with Vista Home Premium preinstalled.
Now I'v got major boot problems. Something happened when I yesterbay tried to install a new driver.

I'm asked to boot with Startup repair (or something like that in english, Startreparation in swedish). Then the computer hangs and nothing more happens. I can also choose Start Windows normally, but that will also hang my cpu.

I've tried to boot from CD-rom but that does't work. (The cpu doesn't even try to read the CD.

Increddibly thankful for replies with help included.