XP media center Login Logout Loop

Have you tried to boot into safe mode yet ? Press F8 upon bootup and select safe mode.


Sounds like you may have been hit with malware

Go through this malware removal steps
Download  combofix.exe and save it to your desktop
Close any open browsers.
Before starting ComboFix disable and exit any anti-virus software, anti-spyware or any other security related software as they may interfere with ComboFix's operation.
Double click combofix.exe & follow the prompts.
When finished, it shall produce a log for you and display it on your desktop called c:\combofix.txt. By default this log is located on your 'C' drive. Post that log in your next reply along with a fresh HJT log as well
Note:Do not mouseclick combofix's window whilst it's running. That may cause it to stall.
Combofix http://download.bleepingcomputer.com/sUBs/ComboFix.exe

Also go to http://www.tomcoyote.org/hjt download hijack this run it and post the logfile here


If combofix reports it removed files then continue on through this if not then post it's logfile and a hijack this logfile

I would then get

http://www.ccleaner.com   download it and run it to clear out all the windows junk files and make the scans faster.

http://www.superantispyware.com download it update it and run it

http://security.kolla.de spybot s&d - download it install it (do not install tea timer, ) update it then run it

http://pack.google.com/intl/en/pack_installer_new.html?hl=en&gl=us&utm_source=en_US-et-more&utm_medium=et&utm_campaign=en_US&ciNum=11    - select to only download and install spyware doctor.

online anti virus scanners

http://www.pandasoftware.com   - panda activescan
http://www.bitdefender.com
http://housecall.trendmicro.com

Make sure you have the MSGINA.DLL File on the system and also make sure it is referenced properly in the system

Open the registry editor and look for this entry:

HKLM\Software\Microsoft\Windows NT\CurrentVersion\Winlogon\GinaDLL = "C:\windows\system32\MSGINA.DLL"   It shoud read as this anything else is a virus unless it is on a novell network

Do you have your Windows CD ??? Do the following

Insert the Windows XP CD into your computer's CD drive or DVD drive, and then restart your computer.
2. When the "Press any key to boot from CD" message appears on the screen, press a key to start your computer from the Windows XP CD.

Note Your computer must be configured to start from the CD drive or DVD drive. For more information about how to configure your computer to start from the CD drive or DVD drive, see your computer's documentation or contact your computer manufacturer.
3. You receive the following message on the Welcome to Setup screen that appears:
This portion of the Setup program prepares Microsoft Windows XP to run on your computer:

To setup Windows XP now, press ENTER.

To repair a Windows XP installation by using Recovery Console, press R.

To quit Setup without installing Windows XP, press F3.  
4. Press ENTER to set up Windows XP.
5. On the Windows XP Licensing Agreement screen, press F8 to agree to the license agreement.
6. Make sure that your current installation of Windows XP is selected in the box, and then press R to repair Windows XP.

Note If Windows XP was preinstalled on your computer, and you do not have the Repair option, contact your computer manufacturer to make sure that you have the installation CD for a repair install.
7. Follow the instructions that appear on the screen to reinstall Windows XP. After you repair Windows XP, you may have to reactivate your copy of Windows XP.
 

Then after doing that I would check for malware on the machine this should repair it so you can gain access once again.