Computer keeps restarting itself

I have an HP laptop, and it keeps restarting itself. It'll boot, and I can log in, but it only stays on for about 60 seconds or so, then shuts everything down and restarts. It does the same thing in Safe Mode with Networking, however it'll stay on in normal Safe Mode (no networking). This morning when I first turned it on, it went to a black screen and said something about a hard disk? And I think it tried to repair itself? Since then it's been doing the restart itself every 60 seconds or so thing.. Also, for a while a Microsoft notification pops up when the computer was turned on asking to make changes to the computer. For a while I've said no, but today I said yes and it went in and said it partially removed malicious software, when I clicked the details about it, it said it was a trogan. It told me to run an anti-virus software to finish removing it, but before I could try, it shut off again.. In normal Safe Mode I ran a full system scan with Norton 360. It said there weren't any risks detected. Tried pulling the computer up normally, still restarts itself after about 60 seconds. Before I did the scan I tried going to Run in the Start menu on Safe Mode and typing msconfig and disabling everything in startup, and then restarted it to see if that would help, but it still restarts itself. I have no idea what to do, and I don't have the money to take it to a shop, and I really don't wanna lose the pictures on it.. Is there anything I can do?