What causes the Windows XP login and then log out issue.
The main thing that causes this issue is there is something wrong with userinit.exe. It is located in the c:\windows\system32 directory.
The issue can be cause by a virus/malware pointing to a seperate file or the file has been removed from the machine. You will need to get the file from another machine and copy it to the drive that is having the issue. I have heard of some people being able to do it from "recovery console" but I didn’t have such luck. If you are still having issues with the machine not loggin in propperly it is best if you boot with a Geek Squad MRI disk. Look in the services section and look for userint.exe. It will most likely be greyed out or "un-checked". Re-check it and save your settings. Reboot. You should now be able to log in.