**No offense Sami**
I don't advise doing the system restore if you have installed a large number of large programs.. it will be atleast as much work as a re-install as any program you have installed which has created registry keys may not work, if it is not written to create them on their -what will now seem like- their first launch!
System restore does not do exactly what the name claims.. it only restores the registry and other important windows folders and files to the date requested. Also any program such as Norton Cleanup or Windows Washer will remove these files as they are meant to be temporary in nature.
I will write a full explanation of a
clean install of XP soon.
Link to the
Clean Install of Windows Without Loss of Data Tutorial