THIS IS A SCAM !!!!  BE WARNED !!!  DO NOT DO ANYTHING THEY ASK YOU TO DO !!! IF YOU DO THEY WILL HAVE FULL ACCESS TO EVERYTHING ON YOUR COMPUTER !!! THEY ARE RANDOMLY CALLING EVERYONE !!!

it is not a scam

Tried it on us too. Indian dude by the name of "Andrew". Talked about firewalls, windows etc. Told us that Windows had notified them that my PC was running slow.

Also received a call from this number saying it was from Technical Department of Windows and advising that there was a virus in my computer - I did go into some components of my computer as asked by "Stephen" but as soon as he asked me to change some setting on the computer I smelt a rat and told him I would call him back - he gave the phone number and I was lucky that my brother was able to check it out for me - I have since had 3 more calls from this person and the last call he was told to p... off.

scam from an indian call centre, claims to be from some division of windows/microsoft or some other PC "doctor", claims victim's PC is infected with some virus/malware  and attempts to trick caller into allowing remote access to the victims PC, or giving out credit card details

Are you Indian by any chance?