By the look of things if Explorer is not working you may have to do a Windows Repair after this to fix that and other programs that are not working..


Do a Restore.
click on the Start button
select Programs
select Accessories
select System Tools
select System Restore
Start the System restore program.
Click the button next to "Restore my computer to an earlier time" and click the "Next" button.
A calendar will appear. Click on the date that you wish to restore Windows to. The box next to the calendar will show you the available restore points from that day. The ones marked "System Checkpoint" are the automatic ones that Windows XP created.
Choose the one you want, then click "Next". Don't pick a point too far back in the past,maybe one week back -- remember, any programs you installed since your restoration point may not work anymore,so you may have to reinstall them.
Reboot your PC.

Hi Pancake

Had completed system restore previously ; internet explorer still not working

Looks as if you will have to do a Windows Repair as your problem does not appear to be malware related...

Thanks for all your help Pancake.