Windows Vista windows keeps shutting down!!

I don't really know that much about techie computer stuff so haven't a clue what to do.

It first started when i tried to access my Learn direct course for the first time which required me to download a Authorware Web Player. It downloaded but wouldn't start up then my laptop kept shutting down. It done that a few times then seemed ok until a few days ago, i was getting a black screen when i turned on my computer because windows had suddenly shut down. I did a system restore which seemed to work for a few hours before it started shutting down again.
Then when i started up a black screen was coming up saying there was an error with windows registry or something, and needed to reinstall windows and do a factory reset which i did. It was working ok for a while then the same thing has started happening again!! could it be a virus from the Authorware Web Player? I haven't a clue what to do.

My Laptop has Windows Vista home premium installed.

 

Ok thanks :