after reading all suggestions here....
it amuses me that no one suggested to you the most SIMPLE method...
yes, all of the software mentioned are good.... but its not 100% sure to remove all the malware in ur PC especially when its deep inside the registry. as you mentioned, you already remove most of it but theres still one thats popping out right? maybe that one is running along with an essential program windows is using.
i suggest that after/before you downloaded the CCleaner, AVG and SpyBot S&D(highly recomended), you make a SYSTEM RESTORE 1st. its in the system tools in your window XP. start>acessories>system tool>system restore. just hope that you havent deleted the restore point in which your laptop works without the viruses.
doing this while running windows may lower the chance of restoring it perfectly. so i think you should start your computer in command prompt (follow lvra's instruction but select the one with the command prompt)
i hope you know some basic DOS commands. but yeah...lol!
just go to "C:\Windows\system32\restore"
DOS commands you needed:
type "cd c:" or whatever letter your windows is installed in(ignore the quotes)
type "cd Windows\system32\restore"
then type
rstrui (this is the system restore application)
just follow the steps. and choose the date you think your laptop is still working good. lol!
any questions..ill see you in game later after i go home. i hope this will help.
Rof exits
poof