XP stuck in login-logout loop!

[Epidural needle]

Epidural needle here for the first time!
Bamboozled by an hp compaq with winxp that boots up fine until the logon screen. Attempt to login thru any user starts, reachs a blank background and then the logout process starts with "saving your settings" finally returning to the login page. Safemode start does the same irrespective of account chosen.
Advise me urgently.
kindly pardon me if this issue has been succinctly addressed by the community. Just point me in the right direction, if so!
Thanks

[FlamingClaw]

is the system restore helps?

[Xlphos]

Have you got the xp cd? I suggest repairing it using the XP cd.

Have you tried using the alternative login, I think if you quickly press CTRL+ALT+DEL twice before logging in you may login using the alernative.

[jbisono]

Could be a lot of reasons but, ones i had that problem with mine computer and i fixed it with this tool http://windowsxp.mvps.org/peboot.htm, hope that help you

Regards.