I think this is the same people who called me about a month ago from a restricted number claiming to be from Microsoft. They called me over and over for about three weeks telling me that my computer was in danger of crashing and they have been receiving reports from the computer about errors.
I talked to Microsoft via their website and they told me they don't contact customers like that and that it was most likely a scam. Something wrong with your computer, you contact them not the other way around.
They talked to my mom and conviced her that a certificate on the computer had expired and that for $99 they could renew it for 2 yrs. First they tried to get the money from PayPal but PayPal wouldn't transfer the funds. Then they conviced her to use Western Union. The bank froze the transaction and called because they weren't trying to take $99 but $500. The scammers tried to tell my mom that it was mistake that would be corrected once the transfer took place. Bank told her that was crap and disconnect with these people.
Today (9/18/12) they called again from this number with the same pitch. I know it is them because it's the same bad speaking English heavy on the Indian accent people (and the same sells pitch line). I know a lot of companies have out-sourced to India for call-centers, but one of criteria for working there is that your accent can't be too heavy for customers to understand you. Add to that if Microsoft really wanted to contact you, they would send an email.
Be carefull. I was told by a Microsoft tech that these people are getting your information through a back door program from either websites or pop-ups. They even stuck fake error messages on my computer to try and convince me something was wrong with it. Microsoft said that they were just fake titles with nothing behind them.
My advise, if these loosers call you, hang up, and take your computer somewhere to get completely debugged and examined for malware.