My Deaktop PC, windows Xp, freezes randomly. CTrl +Alt+ Del doesn't work and the olnly optionis to shutdown by holding the power button. It happens 1-2 times per day, not during any particular work. but it is a pain. no new software installed, no new hardware installed. Any help will be appreciated.
thanks
rpsb

Check the air intake area on the back of the computer and see if there is a buildup of dust/hair/etc on it. Our Dell desktop that the kids use is mounted on the lower shelf on a computer cart and whenever it starts showing that type of symptom the intake is restricted and the heat is building up inside the case. I always look at the intake and fans grills on a desktop before doing anything else. On many (the kids included) you can peel the blockage off like cleaning a lint screen on a clothes dryer, especially if there are pets in the vicinity. Many times the symptoms go away with the air restriction.

Just something quick to check before looking for deeper problems.

thanks, air intake and out are all fine and I clean them regularly.

guess you can stress test your system with memtest (ram) and prime95 (cpu).

you should also do full hard drive scan to see if you have any corrupted parts.

The first step would be to bring the task manager up and see what processes are running.

Also limit what is loading whe your PC first starts. Out of the box, most of those programs, especailly crap ware, load and put a drag on memory. Add software by disc or off the web and most likely the same. Unless the program is protecting your system, don't let it load, until you open it. If your system drags after using some bloat ware, see if it still under the Task Manager. The bottom line is even being watchful, I see 36 various processes, 2% CPU usage and 30% usage of the memory.

Random Freezes are hard to track down. I would keep the processes window open throughout the day and when the computer freezes maybe you will see a spike in activity in a certain area. I think there are programs out there that log activity. When the computer freezes, you can view the log and try to triangulate on the source.

I totally agree with a memtest, prime95, scandisk, and defragment. I would also put something in that monitors temps throughout the day and see if your temps are stable.

Asuuming this is a hard freeze, it is usually due to heat or something not seated all the way or loose. Open the case and check the CPU fan to see if it's sporadically slowing down or stopping (common prob). Reseat EVERYTHING - RAM, IDE/SATA cables, PCI cards, power connectors, etc. Run a memtest86 to verify RAM next - a stick can go bad although it's rare.

If that still doesn't fix it, pull out all but minimum required components - one stick of RAM and your boot drive and let it run with prime95 for a couple of hours. Remove all add-on cards. If it doesn't hard lock, add back components one at a time and see if you can isolate the prob.

I did the PC doctor testing and everything came back normal, You guys are all great and I appreciate the suggestions. I will do the tests as suggested and will be back.
thanks

I had this same issue a while ago and my power supply fan had went out. I replaced the power supply and didn't have a problem since.