I recently bought a new pc and didn't realise that anti-virus software was already installed. I then installed my version of Norton AntiVirus which had disastourous consequences! The PC became EXTREMELY slow.
I have managed to remove the one which came pre-installed and the pc appears to be running ok again now although I spent so little time on it before installing Norton that i cannot compare its performance anyway.
Can anyone advise me as to whether this may have caused any software problems.
Worst case scenario one AV perceives the signatures in the others database as a virus and tries to cure/delete/erase The second AV reacts to this hostile action and tries to correct/block. This usually crashes everything. Some people have managed to get two AV running together, but most don't and as there is as far as I'm aware no compatibility list to refer to, the situation is best avoided.