Boot from your Windows cd / dvd?
You don't say which operating system you are using, but if you want to performa clean install:
1) access your BIOS screen (usually by pressing the DEL key as the machine starts)
2) Set the boot sequence to "boot from cd / dvd first"
3) Insert your Windows disk in the drive
4) re-boot and follow the instructions for a clean install
Bear in mind you will lose all data on your drives.
I would re-install the sound card before installation, as this removing it didn't solve your problem.