Even though my main home PC runs Ubuntu, I still keep a finger in the Windows world using VirtualBox virtual machines. I have one such VM running XP and this became nigh on unusable due to the amount of background processing going on. Booting into safe mode and using msconfig to clear out extraneous services and programs running from system start time did help but I went one step further. Norton 360 (version 2 as it happened) was installed on their and inspection of Process Explorer revealed its hoggish inclinations and the fact that it locked down all of its processes to defend itself from the attentions of malware was no help either (I am never a fan of anything that takes control away from me). Removal turned out to be a lengthy process with some cancelling of processes to help it along but all was much quieter following a reboot; the fidgeting had stopped. ZoneAlarm Pro (the free version that was gifted to users for one day only towards the end of 2008). Windows continues to complain about the lack of an antivirus application that it recognises so resolving that is next on the to do list.