many application suddenly open

Put in your xp cdrom and reboot, now tell it to format hd and reinstall

Whoa!!

Don't reinstall until all other possibilities have been tried!!

First off, boot your computer into Safe Mode by pressing and holding down F8 when you switch your computer on. Select Safe Mode from the menu that appears. Your computer will now start the OS with only the basic drivers required, no extras will be started.

Now you are in Safe Mode, scan your PC for viruses and run the adware program you were trying to install (was this Adaware?), also get a copy of SpyBot S&D and run that too.

After you have done that check your system files by clicking Start>Run and typing SFC /scannow in the dialog box, then click OK. This will check your system files and replace them if they are missing or corrupt.

If this does not work try using System Restore to restore your computer to an earlier state. Click Start>Programs>Accessories>System Tools>System Restore. This is an easy to use program and can restore your computer's OS to a working state.

If these don't work post back giving more details of the problem.

Good luck

I can't believe the first response to your question. This isn't an answer but is more like sabotage. Telling someone to erase the computer is not acceptable.

Boot into safe mode and run msconfig. If the programs still start use ALT-F4 to stop them. Hold the ALT key nd press F4. This will close the current window. If it brings up shut down the computer cancell and click on the next thing running.

Click Start, then select run and type msconfig.

Uncheck all the junk that's starting. You need to run virus and spybot software.

What ever you do do not install service pack 2 untill you get your computer cleaned and working properly.

It sounds like you have a load of malware and spyware.

Turn off system restore if it is used in your os.

Download, update, and run the following.

Your Antivirus Software.

If you don?t have a current antivirus You can get a free copy of Computer Associates etrust EZArmorLE
http://www.my-etrust.com/microsoft/

Spybot: Cootie Remover
http://tinyurl.com/ziar

Ad-Aware: Cootie Remover
http://tinyurl.com/tek5

Stinger: Virus Specific Remover
http://vil.nai.com/vil/stinger/
This item will not update through the program. You have to download the new version.

CWshredder: Trojan and Toolbar Cootie Remover
http://tinyurl.com/2bzef
Or
http://tinyurl.com/2k642
Look for the file in English CWShredder.exe

Hijack This:
http://mjc1.com/mirror/hjt/

Hijack This
This program is useful in that it shows what is currently loading on startup. You must know what is good and what is bad. Once you check it and fix it is gone. So be sure. Items you are not sure of do a Google search for them.

You can save the HiJack This log and post it here as a comment.

Lee