Computer shuts off during start up

My sister has been having some issues with her computer lately. We'll go to turn it on and it will get bast the initial start up screen where you can choose to go to boot menu or bios, then it will come up with a screen that says something about it being due to a recent hardware or software change. Don't quite know what that means or where to go from here so any help would be appreciated.

 

It doesn't boot all the way up to where you can see that windows is loading, the screen that says the thing about the hardware or software change has to options, either start windows normally or recovery tools i think. Regardless of which option we choose, it shuts down pretty much immediately after.

 

she's running windows vistsa and its an emachine thats about 2-3 years old

 

Could be a bad RAM stick. If you have more than one, try removing one to see if it boots.
Box clean? :wave:wave