Virus/Worm ?? Can't log in to windows and BSOD when trying safe mode

I'm trying to work on my step-daughter's computer. It's a DELL XPS410 running Windows XP Media Center Edition. I'm not sure if this is the forum to post this or if it's hardware, operating system or what but she did mention having a lot of pop-ups and running AV and it having some sort of worm but she couldn't remember the name of it. That's actually what I was going to try to work on, but I'm having a problem that I can't even get Windows to log in to even work on it...not even in safe mode.

The problem it's having is when you boot it up and Windows is trying to start and it gets to Welcome screen and shows her name to login and all. When I click on the name, it shows "Loading personal settings" and shows her desktop picture with no icons, no start menu, etc. then it quickly goes back to the Welcome screen and sometimes shows "logging off" very quickly and sometimes don't, and then I'll see "saving your settings" like when you're logging off to shut down or something. It won't log into windows at all. It's just over and over on that same screen when I try to log in. She doesn't have a Guest login set up so there's no other users on the machine to try and see if it will log in to any of them.

Then, I tried to get into safe mode and it won't. It goes to a BSOD Stop error screen and said:

STOP: 0x0000007E (0x00000005, 0x80537009, 0xF792E508, 0xF792E204)

One time, the BSOD said:

STOP: 0x0000007E (0x00000005, 0x80537009, 0xF78AE508, 0xF78AE204)

So, is this caused from a virus/worm? Is there anything I can do to get this to boot up so that I can try to rid it of the virus/trojan/worm and/or malware?

Thanks in advance.

Please download ComboFix from BleepingComputer.com

Alternate link: GeeksToGo.com

Alternate link: Forospyware.com

Rename ComboFix.exe to commy.exe before you save it to your Desktop

• Disable your AntiVirus and AntiSpyware applications, usually via a right click on the System Tray icon. They may otherwise interfere with our tools A guide to do this can be found here
  
• Click Start>Run then copy paste the following command into the Run box & click OK "%userprofile%\desktop\commy.exe" /stepdel
  
• As part of it's process, ComboFix will check to see if the Microsoft Windows Recovery Console is installed. With malware infections being as they are today, it's strongly recommended to have this pre-installed on your machine before doing any malware removal. It will allow you to boot up into a special recovery/repair mode that will allow us to more easily help you should your computer have a problem after an attempted removal of malware.
  
• Follow the prompts to allow ComboFix to download and install the Microsoft Windows Recovery Console, and when prompted, agree to the End-User License Agreement to install the Microsoft Windows Recovery Console

Please note: If the Microsoft Windows Recovery Console is already installed, ComboFix will continue it's malware removal procedures.

Once the Microsoft Windows Recovery Console is installed using ComboFix, you should see the following message:

• Click on Yes, to continue scanning for malware.
  
• When finished, it shall produce a log for you. Please include the contents of C:\ComboFix.txt in your next reply.
  

I'm not able to download ComboFix right now because I'm not even able to log into Windows.

Please do the following on another computer, if possible:

Avira AntiVir Rescue System is a Linux-based application that allows accessing computers that cannot be booted anymore.

• Download The Avira AntiVir Rescue System from Antivir.de.
  
• Just double-click on the rescue system package to burn it to a CD/DVD.
  
• Then please use that CD/DVD with Avira Rescue System to boot your computer.

You'll get a boot option to either boot from hard drive or AntiVir Rescue System.


Press the number 2 on your keyboard to boot into AntiVir Rescue System.

Please wait until drivers are loaded and Main menu shows. Then please select the second option “Scan your system with AntiVir” and hit Enter.


Under Configuration, please select Scan all files, Try to repair infected files and Rename files if they cannot be removed?.


Then please start the scan.

The Avira AntiVir Rescue System wil now

• repair a damaged system,
  
• rescue data,
  
• scan the system for virus infections.