Old School Windows 2000 pro

Lately my computer caught a virus. I just know i have to have the original OS disk to reinstall it. the problem is that we bought it OEM meaning it did not come with the disk and the seller moved far away. I'm somewhat sure it was a legal copy as it was registered with MS and had all the patches allowing MS to inspect my computer several times. $140 for a Full Disk is rediculous and I feel like the whole thing is/was a set-up. I have always been for purchasing the hard copy of any program I like but the price is now rediculous. Anybody know of a cheap cheap place other than Ebay? I'm ready to make a Utube video out of this computer.