>> I've come across many viruses in my time (not as many as Kitz though Wink )
I first became really interested in them when doing my dissertation and I got sidetracked for a while as [enter geek mode] I found them quite interesting [/end geek mode].
Once upon a time I used to earn a "bit of beer money" cleaning up infected PCs and I used to be well up on whatever was the latest doing the rounds and I used to be quite stubborn in not letting one defeat me.
I think the only ones Ive given up on were both in about the early 2000's:
One was a ladies PCs which was fairly old and had been infected with one of the CIH viruses which practically wipes the HDD and also over writes the BIOs.. that was a real nasty and in the end needed a new mo-bo.
The other was SQL-slammer. PC got infected on the actual night of release into the wild. There was no fix and no AV that protected against it at the time.
These days I dont really see that much of them and its only really the odd occasion when rescuing friends PCs etc.