my pc is full of viruses and not workign and therefore need flattening ( totally clearning the harddrive etc: so nothign is on ) i have a rough idea of how to do it but need it explaing to make sure im right thanks X
You need to format!! put the windows XP disc in and follow the on screen instructions, when you get the opportunity for a full format, take it. You will lose everything so ensure you have everything backed up.
As RATTER15 said just put in your original XP Disc then reboot the pc and it will then give instructions for formatting your hard drive and wiping everything. Make make sure you have the serial number of your XP software. You will eventually be asked for this and as said before everything WILL be wiped so make sure you back up your stuff.
As a first step you do a system restore to a date when the system was OK. If that fails you should try a recover operation. Some PCs will allow you to do this without wiping off all your data files, etc. If this still fails a complete recovery is necessary and like the previous callers involves a Format, but I would not do the format yourself leave it to the recovery disk as this will also take you through the setup process and install the necessary files.