Win XP Pro Admin cannot log in

[Radical789]

I am working an a Win XP machine for a friend. At the Welcome Screen the only user name icon that displays is Administrator. When I click on that icon it hesitates for a few seconds and then comes right back to that Welcome Screen with the Admin icon. The same thing happens in the Safe Mode.
There's no telling what he has done to the operating system. I don't know if the Admin has a password or not because it never asks for one. I have a feeling that there has never been an admin password. Is there a back door into the system? I'm not sure if "resetting" the admin password will help because it never asks for one to start.
Could this be malware? Is there a way to scan a system without it logging in?
I am trying to avoid wiping out the drive and reinstalling the OS if I can.
Any suggestions are apprciated.
Carol

 

[MedicBob]

Control Alt Delete twice, then user name= Administrator Password= ? might be blank

 

[RebateMonger]

There's some malware that can cause symptoms like this. You can't log in. I did a recovery of a client's laptop with this problem.

1) The Userinit.exe file was missing from the c:\windows\system32 folder. This made it impossible to log onto the PC. I booted with BART and copied that file from a functional XP computer to the damaged computer. I may have had to make a Registry edit, too. I don't recall. If you Google for your symptoms, you can see this issue and its repair.

2) The recent "MS Anti-Spyware 2009" rogue spyware program had been installed on the PC and was issuing its constant warnings about malware being installed and offering to remove it.

3) There were also a couple more incidental pieces of malware installed, including Trojan.Dropper, Trojan.Downloader, and some viruses.

4) The USB ports didn't appear functional, maybe something to do with the malware.

I removed the malware with MalwareBytes' Anti-Malware software.

 

[Radical789]

I will give this a try, thanks for the reply.

 

[Radical789]

I have seen that MS Anti-Spyware on other machines. I will try that software you recommended to scan this machine and others that I might see that malware on.
Thanks for the reply!

 

[Radical789]

That userinit was missingandthat did the trick. I am scanning the system right now with the Malwarebytes Anti-Malware and it has already found some items.
Thanks a lot for your help!