Oh dear, this is a scam, and there were no problems with your computer. But now you've let these people take control of your computer by linking into it, they've probably done all sorts while there, such as scanning information etc. I do hope they haven't got any confidential info from it. Maybe there are now innumerable viruses too. Better get some technical help to protect yourself, and check exactly what they've done to your private data. Oh dear!