|Depending on the age of your computer you may feel inclined to upgrade to win-7 anon.|
You could run the M$ win-7 checking utility to see what is OK and what isn't. Any drivers not included in win-7 are very likely available "out there" for free.
You can get an OEM or reconditioned software disk - either actual disk or a legitimate download for around £45.00 or local equivalent. You would get a new installation key as well. The OEM or reconditioned software disk will be tied to the motherboard, so you couldn't install it later on another (newer?) system. With a retail disk you could.
What make and model computer do you have?
OEM and reconditioned software disk as essentially the same. OEM is usually used by those building "new" systems; reconditioned by those upgrading older systems to win-7 (typically from xp or vista). But they are otherwise no different as best I understand...