Networking Experts Plz Plz Help Plz.....!!!!!

[Manjan]

Asalam-o-Alaikum,
Dear Experts, I have 2 problems on my Network.

1. System Cannot Log me On to my Domain

Error Massage: The system cannot log you on to this domain because the system's computer account in its primary domain is missing or the password on that account is incorrect.

2. Access Denied When accessing the Network Drive

My Communication between Servers and Workstations is absolutely fine, but any kind of file shearing is denied by the servers randomly, like Network drive & Printer shearing Etc.....

Please Guys tell me how can i fix this problem, i have receive this errors several times in a day on a different workstations, many times i rejoin the domain & re create the SID account on a AD but it not longer work for me.

ENVOIREMENT: Windows 2000 Server With Service Pack 4,
Primary Domain & Secondary domain both i have using on a 2 servers.
Active Directory, DHCP, DNS and other services are enable.
Windows XP base Work stations.

Regards,
Syed Tauseef Ahmed