Windows 2000 Logon Problem

i installed win2000 on my system. things have been alright till yesterday. now when i try to logon to windows 2000 it does the following:

1. after presentation of the logon screen. i type in the account name and password. and then click on ok

2. afterwards it tells me its loading my personal settings, then its apply them

3. next it tells me its saving my personal settings. (apparently logging me out)

4. it then displays the logon screen again.

this occurs for all accounts including the administrator account.

any idea of whats happening and what i could do to remedy it.