Hi all you IT boffins out there........(he says longfully

)
I feel my PC is in need of a spring clean. Over the past 3 years I've added and removed programs, had viruses, detected spyware etc and am still having odd things happen that naturally shouldn't under XP SP2.
I'm wanting to format my C:\ as I feel this is the only way to rid my machine of all the cr@p that stays behind when you 'remove' applications under 'Control Panel', all the trojans etc and get my PC back to something like the lightning fast work aid it once was.
I've scoured the net to find the best way of doing a format under XP Pro and it seems it's best to do it via the Setup CD.
Firstly, I removed SP2 cos the setup wouldn't run under the 'later version of Windows' scenario
I run the setup, but don't see an option to format - there's only options to do a 'new' install or an 'upgrade'.
I chose 'new' and followed the normal screens. As setup commenced it seemed to go back to a DOS style blue screen with the command "to continue setup insert your 'Windows XP setup CD and press ENTER'. I do this but the message just remains. I can't seem to get the process to go past this screen. The only options I have on the DOS style screen are F3 to Exit and F8 to Continue which as just staed goes nowhere. Even when I eject the CD and re-insert it, nothing happens.
Does anyone know what may be causing this or how I can get around it please???
Shout if you need anymore info from me.
Many thanks, Guy