I was browsing through websites and suddenly my computer threw alerts on my screen saying my computer is being invaded by such and such viruses and you need to quarantine them now. It then proceeded to download 5-6 programs right onto my desktop so I could RUN them and eliminate the viruses. Obviously being the skeptical person I am I just stopped what I was doing and ran a McAfee scan- which showed up clear, no detections. I deleted all the files that appeared. The icons that appeared like they came from Microsoft but could have been fake I guess. In the future I will continue to trust McAfee but if those were Microsoft website downloads, how would I know and aren't they just as safe? I have Windows XP and I have two computers on my network. Both were clear of viruses.
Microsoft usually gives you alert if there are any updates pending for your computer.This information would be available on the lower right corner of the computer with Microsft Shield icon. If you are getting any automatic popups while browsing websites , even though they look like microsoft updates always try to ignore them by installing them you could bring some Malwares.
So always try to do a Update when prompted or do a manual updates.Do not trust and install other automatic popup while browsing.