I don't know whether this would help IO 540's problem, but a little while ago I found myself supply teaching at a school which had gone "computer crazy". They had installed a radio LAN to cover the whole building with appropriately protected internet access e.t.c, e.t.c. All pupils were issued with a laptop which they paid the school so much a month for and at the end of a period the laptop belonged to them. All these laptops had standard software installed and, naturally they picked up viruses and other nasties from time to time. When a kid had such a problem, they took their machine to the school's I.T. technician who merely re-formatted the hard drive and uploaded the school's standard hard drive files. This included XP - the lot and naturally the virus/adaware/popup/spyware problem was cured. It also meant that the kid concerned lost all their favourite software that they had uploaded including game saves and so on. Thus there was a real incentiive to be careful. It certainly worked for them!
P.P.