error message: stystem32/ntoskrnl.exe

hello!

the trouble pc is a compact presario running window xp.

i hope that this is the right forum for this headache. i did not know where to post it.

i don't know what happen... 1 mn i was online then i was not able to type anything + the computer was kind of slow. so i decided to reboot the pc. when it came back online again... omg... i don't know what happen to it. nothing work.
i can't run any prg. i can't get to "all programs" it will just flash really quick then it would be gone.

I could not run malwarebyte or Avast to see if the pc had caught a virus. it won't let me do it.

so i reboot the pc again, trying to access safe mode... it did not let me do it too.
instead i got a message saying:

\system32\ntoskrnl.exe.
Please reinstall a copy of the above file.

i don't really know what it means or what i should do.
note that i do have a backup system recovery CD somewhere... not sure if it will help.

can someone help me?

superb 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.