Windows 2000/2003 Security

Hi, On one of my 2000 Domains, all accounts are being locked out. If I unlock an account, it will be locked again within a few minutes, even an account that no-one or nothing uses. I have lots of errors like ...

I am currently logged on as an administrator account and locked my self out from c:\ by making mistakes on the security tab under properties. Everytime I try to open up my c:\, it says "c:\ is not accessible. Access is ...

need some help here please, i reinstall windows XP SP 2 and now all my encrypted files cannot be restored / opened(cannot decrypted) i already create a same username and password. i also tried to make the computer name the same too ...

trying to install update but keeps failing..Security Update for Windows XP (KB956803 anyone have any suggestions???? ...