Never EVER talk to, call back or (for sure) let someone have 'control' of your computer who cold calls you.
With the millions of computers out here just how do they know your computer is running slow or needs repairs??
If you don't recognize the number DO NOT answer the phone, if they are legit they will leave a message.
This applies to your cell phone also.
Called me today - I don't answer numbers I don't recognize.
Please people, don't EVER give them access to your computer. I can almost promise if you do, you will live to regret it.
Safest bet - don't answer.
Also, some of these numbers aren't listed with a real business so being on the no-call list doesn't help.
I got a call last week and caller id showed 495. That was all, just 495.