Spyware, viruses, & security forum: Is there a Microsoft Scam going on these days?

Dell Intel Core 2 Duo Processor E7500 Computer
Inspirion 545s 00
Windows 7 Home Premium 64-bit
6GB Memory
750GB Hard Drive

Tonight I received my 2nd call in about 3 weeks from "supposedly" Microsoft. The first caller was a man and when answering the phone, he said "This is Microsoft Windows 7 calling, and your computer has been reported as being full of virii and malware." He said, "I'm here to help you rid your computer from all infections." I told him, "I don't think so, as first MS would not call me personally, and secondly, I help teach pc classes and am aware of what I must do to keep my computer clean." I asked him for his name a couple of times, and he would only state, "This is Microsoft Windows 7 calling." The 3rd time I asked his name, he hung up on me.

Tonight's call was a bit different, but the gist was the same. A lady called identifying herself as Anna, with Microsoft Windows. She said nothing about "7", and she did provide her name. It sounded quite professional as the background noise reminded me of a Jerry Lewis Telethon. She said my computer had been reported to them as being full of malware and viruses, and she wanted to take my computer remotely and get my computer back up to speed.

I might add that when checking caller ID, is shows the telephone # as unavailable.

Well, first of all, my computer is giving me no problems whatsoever; secondly, I've been under the assumption that Microsoft will not call you directly about anything. Thirdly, I did just happen to run Malwarebytes recently, and it was as clean as a whistle. My Avast scans show me clean as well. I use CCleaner on a regular basis, and I just think it's all a scam.

Is anyone aware of something like this happening around the globe? I'm also aware recently some people posing as Microsoft individuals tried to scam a government agency in this same manner but did not succeed.

Any thoughts out there? No way do I plan to turn my computer over to another individual remotely or non-remotely (LOL).

Julea