Virus in non existant lap top.

Oh dear Frank, pay attention...this is a long standing scam....its been around for several years now. Just ignore any such calls.

I agree with HildaW 100%. The caller, might even suggest that they belong to the ISP [ Internet Service Provider ], that you actually use. Not so, they are still trying to scam you out of cash. So beware and ignore.

Ask them which computer they are talking about. It is such fun if you sound dim and worried, it really gets them thinking they have found a mug! I named 4 different ones which we don't have and they told me it was the Acer! Then I strung them on for a bit longer before asking them if they really thought I was that stupid. If you have the time you can really waste theirs.

Movedalot..........you tinker, mind you my husband has done the same on a day he was supposed to be working and was bored! He pretended to be quite befuddled and had great fun.

This has happened several times when I have been house/cat sitting for DS and family. My tactic is to say that they have an Apple computer and that shuts them up well and truly. They don't have an Apple, just a selection of more or less decrepit laptops.

I'm another one who sometimes takes great delight in strinnging them along. OH even got them to put the phone down on him by being soooooo dim!

I love that 'dim' approach too. Give them a run for their money. Pretend to go along with it and play the 'Your computer?' game when they ask you to click on My Computer (but don't click of course!) I managed to waste their time keep them on the line for almost 20 minutes last time. Great fun on a dull afternoon.
Be careful of the latest scam on credit cards. They ring you and say there's been unusual activity or your card and they are sending a courier to collect it. What makes this more believable is they tell you to hang up and dial the number on the back of your card to confirm. In fact they haven't hung up themselves and you end up calling them or their fellow scammers.

Yes Aka never believe a caller is from your bank or credit card provider. Always call them back on another phone or if you don't have one try calling a number of someone you know instead of the bank and see what happens. Alternatively wait half an hour before making the call, they will have got bored by then.