Are you sure these are virus infections or perhaps a mixture of viruses and spyware or perhaps all spyware? It doesn't sound as though the system has either anti-virus or anti-spyware software installed.
When was the last time the system had a good clean? Running Ccleaner, Spybot Search & Destroy and SuperAntiSpyware may well clear most of it out.
Any way to your specific question it won't format because Windoze is installed on Drive C: and the C: drive is mounted. To format it you have to unmount first.
If you really want to do this shut the machine down completely. Put the OS Installation CD in the drive. You may need to alter the BIOS settings to tell the M/C to boot from CD rather than HD.
With the first screen of the setup program select "R" to enable repair mode, select a Windows installation for repair and input it's admin password.
On the command line console that now appears enter "map". You should now get an overview of all HD partitions and corresponding drive letters.
You can now type "format C:" and off it will go. It will format using the exisiting file system but you can force another (if you want) by typing an additional command. Fo example to force NTFS type "format C: /fs:ntfs"
But if it's an existing XP installation it will be NTFS anyhow.
Thanks for the replies, I decided to get a friend to have a look at it.
He installed Norton Antivirus, the computer is all working now, he removed a few infections but says thre's virus there that needs removing and he recommends formatting and starting from scratch ?? good idea ?
I've been playing around with my computer which is protected by McAfee Security center - it's always popping up telling me not to do something or asking to remove something - which I always follow and click yes to remove any suspicious files.
I don't know much about computers, when you do a virus scan it says: