Computer turns itself completely off during file transfer...

Hello...I'm not sure if this is the right section to post in, but I hope some of you could shed some light on my problem. My computer (Toshiba Satellite 1955-S805, laptop) has been shutting down on its own lately, but I've noticed it mainly happens during file transfer such as music. Here are a few of the occurances that I have written down. It crashed when it was reading songs prior to burning them to a CD, it crashed when moving songs over to my ipod, and it crashed when importing songs from a CD to itunes. It also shuts down every time I try to run a full system scan using adaware. I can run a smart scan using adaware and it gets through that just fine. Please shed some light on my problem. I'm running Windows XP home. Thanks in advance.