Computer logs on then logs off

[aroostook]

I have a computer here that just today started asking people for a password (there's no password on this machine). Knowing there's no password, they just log on. And the computer does log the person on...then immediately log them off again, and put them back at the password screen (not the usual "Welcome" screen with the cutesy pictures but the W2K-based password prompt).

Any ideas?

 

[Lemon13]

did u try savemode, what is then?
try:

http://www.winxptutor.com/wsaremove.htm

 

[aroostook]

Yup. Did Safe Mode (still logged in then logged right out again). Tried "Last Known Good" for kicks and grins, too.

Had not thought of malware, but it is possible. I'll try the suggestion on that link. Thanks!

 

[smah]

The most common cause of this behavior is registry corruption. Often the reason for for this registry corruption is the physical disk.

Step 1 is to boot into the Recovery Console & run chkdsk /r. Let it run to completion, no matter how long it takes.
How to install and use the Recovery Console in Windows XP

 

[linney]

Some things for you to look at.

Logon - Logoff loop, also caused by BlazeFind

http://www.winxptutor.com/wsaremove.htm

http://www.paulscomputerservice.net/index.php?body=./os/autoLogoff.php

Log in Logs straight back Out
Thread779-924408

logs you on loads personal settings then logs you off?
Thread779-919265

A second reason can be security policy settings:
Fast User Switching and Welcome Screen in Windows XP

http://exodusdev.com/tech-tips/windows-xp-pro-login-problems

HOW TO: Install and Use the Recovery Console for Windows XP (Q307654)

http://support.microsoft.com/support/kb/articles/q307/6/54.asp

An easy to follow recovery console description when unable to start computer due to corrupt registry.

http://www.digitalwebcast.com/2002/03_mar/tutorials/cw_boot_toot.htm

This is a layman's version of Q307545 in simple language.

Removing adware & spyware
FAQ608-4650

 

[aroostook]

linney:

Your links were the cat's pajamas. Especially the 3rd one. Thanks, all!