abOut the virus thing sites like mygpt gives tips and warning when yOu dO autosurf prOgrams...

having antivirus and firewall wOuld be very gOod
clearing the cookies is also one sO yOur system wOnt be clOgged...
and its always yOur choice if yOu think its damaging yOur system...
if yOur planning tO dO it when yOu run the prOgram try Observing
first if its running smoothly on your PC