Desktop

could be an MB problem or power problems. I used to toast HDD's frequently because of low voltage (I am at the end of the line on the strip). I installed a UPS and replaced the system and havent had major problems since.

Your system is of the "right" age to be part of the first major batch of motherboards with bad filter capacitors.

Near the CPU, look at the cylindrical parts with metal tops.
If the parts have bulged, or there is material oozing from the bottom of the parts, you have bad capacitors.

There are a couple of new TR articles and discussion threads related to a new round of capacitor failures.

As stated in the first answer, you might also have problems with your power supply.

Chas

Your problem comes from your PSU with 300W. It is pour for your configuration. You need to replace your PSU with at least of 400W. Your moving components after a function time need more power, and it same to be your case, when 300W is not enough for you.

4 yr old ? Clean it up lately ? anti-spyware, latest updates on anti-virus ? windows updates ? chkdsk/r ? defrag ?

Did it always freeze intermittantly ? When it was totally OEM ? If you have not been to a spy site, picked up a bug ? changed anti-virus ? changed anti-spyware ? Tightened up on anti-virus or added anti-spyware ?

Is the Dimm tosted or is it the slot ? Makes a BIG difference ! Swapping the Dimms will tell you a lot !

What was added before freezing ? Dimm or HD ?

PSU should provide enough power for what you have.

Sorry, I only have questions, more answers would be forthcoming if my questions had answers to give you a solid solution to your problem.

Don't reboot until you have swapped out the power supply.

If this toasted your RAM it certainly sounds like your power supply. Don't boot it up or you might toast the PC!

Make sur eusing asurge suppressor/votage regulator

Don't reboot until you have swapped out the power supply.

If this toasted your RAM it certainly sounds like your power supply. Don't boot it up or you might toast the PC!

Make sure you are using a surge suppressor/voltage regulator

look for blisters in the capacitors, if they have replace your motherboard with new one

Freq. Freeze: My 2 year old Toshiba A25 had the same problem for several months. After a lot of trouble shooting I found one of two 256MB memory sticks had gone bad. I changed the memory stick & have not had a freeze up since. wagnerND

Freezes as you decsribe are usually hardware. Unfortunately it becomes a matter of illiminating the possibilities.
1. Make sure your hard drive tests correctly.
2. Look for faulty filter capacitors on the motherboard and in the power supply. If the power supply is in doubt change it. They are cheap enough.
3. Check out memory. If one toasted that could be serious. Will the system run on one module? Have you run a memory diagnostic. Do a Google search for a free diagnostic such a MemTest86.
4. You could have a motherboard failure. This will be hard to identify without diagnostic gear.

Recently I has a Celeron 1500 system with a similar problem. Diagnostic software revealed that the hard drive was not being reported correctly. A problem with the motherboard controller. We had to replace the motherboard, processor, memory and graphics(internal on motherboard)

Not an easy task.
All the best