Windows 2000 Installation failure

I have a home built computer with a AMD 950MHZ processor, ABIT KT7 MB, 512 SDRAM, WD 30MB HDD and Sony 54x CDROM. This computer was originally loaded with Win98SE. After failure to remove spyware and possible virus’, I reformatted the HD and attempted to load Win2K. The install fails when attempting to load .dll files. I tried a new WD 80GB HDD and still have the have problem. I also tried installating WinXP and still have the same problem. Would the BIOS (currently running Awards v6.0) be a possible problem. I am able to reload Win98 with no problems. Don’t know what the problem is. Can anyone see the error of my ways?