I have just had a call from this company but luckily knew what they were up to as we had receined a call from another company along the same lines. The caller ID on my telephone shows overseas & is a foreign voice on a very bad connection. I asked for the company name - Techis online - and a phone number which was in Brisbane, Australia. Of course it only goes to an answering machine.
Do not connect your computer and follow their instructions. If you do, they will try to sell you virus protection which you already have from a reliable source.