Hi i have just bought from a boot sale a AMD athlon pc with 512mb ddr ram etc 500mb hard drive, i started it up and runs windows xp well but its fill of viruses, spam etc and god knows what else.
I cant reinstall xp as i have not got the cd so need to clean it what procedure and what tools would you use for viruses, malware,trojans etc etc.
Not the answer you want to hear but a re-install would definitely be the best way to go - even cleaned up it doesn't sound as though it's going to be a trustworthy machine. Also if it's that full of crud then a fresh install is likely to improve performance somewhat, especially with limited RAM.
Is it a recognised brand? You might be able to get system recovery disks from the original manufacturer.
The other thing to check for is a system recovery partition on the hard drive.