Power light comes on and then goes off.

SOURCE: I have Aspire 5520-5912 Notebook. When I turn on

Sounds like you got a virus or may have been fitted with the wrong power adapter. Because of the complexity of laptop computers, I recommend having the geek squad at your local Bestbuy troubleshoot this matter.

You need a professional who can actually see what's going on to properly troubleshoot this issue. Geek Squad is the best of the pros, and my friend in technology.

Have them check to see that your harddrive is operating properly, and that your computer is not having internal power issues. If your laptop is still under warranty, often Geek Squad can honor a manufacturer warranty, saving you a lot of money.