XP shuts down. No error codes. No blue screen.

I tagged this on to a session that was resolved previously. I doubt if that is following the protocall...sorry.
My XP just closes without warning. I get no pre warning and nothing afterwards. It just closes and sometimes it restarts and sometimes not. It will close in less than 2 mins. or maybe wait for an hour or better...it follows no set pattern. I have been heavy into searching mobile apps. for the past couple of weeks and this started while I was downloading and transfering apps.yesterday....
I managed to keep it running long enough to do an Ad-Aware scan and a Malwarebytes scan with nothing found.
Have mercy on me .....I am redused to using my laptop with Vista......

Thanks flyinskwurl

Hello,

Make sure that your laptop has good ventilation and that not air flow is blocked (by dust etc.). It's best if your laptop is placed on a flat surface.

Sorry I gave misleading info. The problem I am having is with my desk top computer. I have opened the case and cleaned out the air intakes, fans and processor. That didn't change anything. Ventilation seems good.
I have discovered that I can boot up in Safe Mode and it keeps running...but as soon as I boot up in normal mode it will let me sign in and then shuts down to just a black screen. The HD seems to keep running.. seems like only the os is shutting down.

Hello,

Could be malware. Open a new topic here: http://www.geekpolice.net/virus-spyware-malware-removal-f11/

To get your computer checked.