Windows Xp Login Problems?

Ouch.

There are numerous ways depending on how well you messed up your operating system.

When booting hold down f8 and select safe mode from the boot selection. It sounds like the "last known good configuration" option won't work in this case but feel free to try.

After you log in to safe mode. Try to restart normally. If you can't lof in normally go back to safe mode and see if you have a valid restore point to return back to.

If no joy from safe mode its recovery console time.

Pop in your XP disc (cos you have a genuine copy of course) and reboot (make sure your bios boots from Cd/DVD drive before hard drive)

Press any key. when prompted

Let windows do its thing (may take a while) then when you have the chance select the partition to repair.

you will coem to a command prompt type environment. If you don't have an admin password just press enter.

use this command.

chkdsk /r (you may need to select the drive by its letter)

cross your fingers and be patient it takes some time.

There are a number of other commands that you can carry out from here but its a lot of info and I would need to be sat at your pc to really know which way to go but chkdsk is a good start. You may need to rebuild your registry or system files... Quite possibly the malware destroyed, corrupted, or the removal of the malware led to demise of system critical files. If you get in through safe mode. You will be able to source these problems by reading and documenting error messages or looking at error logs in the admin tools facility in control panel.

Good luck.

F8 into Safe Mode just after the boot screen. Choose Safe Mode with networking. Log in as administrator or your login. run Start>All programs>Accessories>System Tools>System restore. Choose the last restore point before installing Spyware Doctor. reboot as it asks and you should be up and running. uninstall Spyware doctor. You might try Spy Sweeper from webroot.com. Its a lot better than others.

If there were other events that could of lead to a new virus/spyware, it seems like someones set a start-up item so that it runs the log off whenever your start up.

Try booting into safemode. [press F8 twice during boot]

log in as the Administrator account

Press WIN+R [win is the windows logo]

type "msconfig"

click the startup tab and look for any odd files like .bat and disable them.

Also check in C:\documents and settings\username\start menu

\Programs\Startup and C:\documents and settings\all users\start menu

\Programs\Startup for any odd files.

The rest that you can't remember is what tells you what's wrong with your computer.  Next time it happens, note down the STOP error number (it will say STOP 0x00...).  If you can't do that, then take a photo of it, upload it to Photobucket or similar, and include a link to it in your question.  

i would boot into safemode, and uninstall spyware doctor and install spybot... if that didnt work i would do a xp repair

Contact a computer expert and see what they can do about the problem.

reinstall windows but back everything up first