I am using genuine windows xp pro version and my computer keeps restarting when login in to the domain user. but it is working fine when login in local administrator. could someone tell me what could be the reason why this is happening. i have changed the motherboard also. this is HP dx2310 machine. McAfee cooperate is installed. this is newly installed windows xp pro service pack 3

Thank you

Do you really mean Domain user (logs onto a domain server) or just a user (account on the computer)

If you do mean domain user... when logging in to a domain as soon as the credntials are verfied a bunch of settings are sent to the computer called policies. I am sure that one of these policies s causing the restart and you will need to scrutenise them from the server removing anything suspicous. It is also possible that this is due to the motherboard change and an easier fix may be to create a new user account on the server.

If you mean local user, just backup your data with dmailer backup here: www.dmailer-backup-software.com from the administartor account and reinstall windows. You do not need to format when you are asked to just select leave current OS in tact however it is a good idea to format and start fresh every few years.(kinda like an oil change)