Windows 2000 boot problems!

HELP! OK, remember my previous problem where I couldn't boot when I installed that 10G HD, but could without. Well, I needed some stuff off my boot HD, so I stuck it in my only other 2000 computer. I get that same screen(yes, it was booting of THIS computer's HD, not the one I just installed) Well, I removed it, and tested the computer to be sure I installed everything correctly. It starts to boot, then gives me that same error! I changed NOTHING on the MB. All I did was disconnect the CD for that HD, and reconnected it once I finished. Could my other HD have a virus that spread to my computer? If so, how can I repair it? I can't get to Windows, safe mode, or command prompt! Of course, I can boot to a disk, but the HD is NTFS...

What can I do???