my hp pavillion a465c powers up then gos to black screen,ask's what you want to do xp-last best known safe mode etc,no matter which one you pick it loops back then sometimes it go's to windows for 5-10mins then shuts down and starts over agin,cant run anti virus no time to run before shut down.power supply ?help
Welcome to the forum. It sounds like your problem is more related to a hardware problem rather than software, so for the moment, forget about running a virus program.
I am doubting that it is a Power Supply problem, but if it loads up and runs for a short length of time, it sort of points to a "Heat" problem.
1. First check that your processor fan is spinning and keeps spinning. (Check all the fans).
2. If the fan is spinning (and keeps spinning), then you might want to check if your processor is properly seated. You might have to remove it and clean the heatsink and processor of all old "paste", and apply new and reseat the heatsink/fan.
3. If you have more than one stick of RAM, check to see that all are properly seated. If you only have one stick remove it and clean the contacts and reseat.
4. Get back to us after you have done that, and hopefully you will have solved the problem. Be sure to let us know one way or the other.