CPU is unworkable or has changed error

Ok heres the problem:

During the POST when my computer boots up it comes up with an error saying "CPU is unworkable or has changed" I used to have this problem before but then i switched to a different brand of memory and the problem went. However due to overheating alot i had to take one of the sticks of RAM out and now get this error again. I have tried using a different bank for the memory and have also gone to the BIOS and "loaded optimized defaults" like a friend suggested. Also in the motherboard manual it suggests after changing the CPU reseting the CMOS (or something simlar to that, its a jumper on the motherboard next to the chip). Also some of the time the computer just freezes during the POST. There are no warning beeps at startup.

Motherboard: Abit NF7 v2.0 nForce2 (Socket A) Motherboard
CPU: AMD Athlon "Thoroughbred" XP 2400+ - OEM
512MB RAM (Used to have to 512MB sticks but downgraded to one)

Any help much apricated. Also when I have both sticks of memory in the CPU is running at about 50 Degrees Centigrade (hence why i took one stick out) Is it safe to just get a more powerfull fan for the CPU and use both sticks or could this damage the CPU anyway?

yes.. you should reset the bios/cmos via the jumper.. just make sure you have the power supply AC cord unplugged or the switch on the supply turned off.. as with most modern setups, there is still power to the mobo.. it's sort of really in a standby type of mode.

this also applies to when you change memory, cpu and peripherals.. make sure you have that power turned off.. I don't think your memory is the cause of any overheating.. most likely, you don't have any decent thermal paste between your cpu and fan/heatsink.. some of these stock amd setups come with like a double sided tape.. it'd be best if you got artic silver paste and a decent cooling rig. and 50 degrees isn't too hot to begin with although you could get it down some. this is a no load temp ?

I presume by no load temp you mean temp taken when theres little cpu activity. Yes this temp is taken from the bios before the computer boots into windows. Anyway thanks for the reply ill have a look into better cooling facilities.

Having two memory sticks won't damage your CPU, as they generate almost no heat.
If one of them is faulty then your PC will crash randomly, but won't cause any physical damage.

'Optimised defaults' may not be good enough if you think you have a hardware problem.
There are all sorts of other BIOS settings that you can change - for example if you think the RAM is suspect, then try changing things like the CAS latency setting to a more conservative value.

50C in idle mode sounds too hot to me - AMD CPUs are well known for generating a lot of heat and need a good cooling system.

Not quite the same, but this P4 system never gets above 50C even when running applications/games that stress the system to the limit.

Have a look at your voltage settings in your BIOS, check your MoBo documentation for the correct settings and clock speeds or check your memory manufacturers web site etc. If you have memory from a "second rate" company you prob wont find the info you need so check out www.crucial.com if needs be. Thay are prob the best around. I dont think the problem lies with your memory but you never know, stranger things have happened!
Good luck.

Kinda late, but it could be that you need two sticks for "Dual-Channel" to be enabled. It offers much better performance I've heard, but only works if you have at least 2 sticks of RAM. If you really want to take a stick out, go into your BIOS and figure out if that can be turned off.

I see no reason to run with only one of your two sticks of RAM unless one is faulty. If you're just concerned about temperatures, you should usually just make sure there is little or no dust inside of your computer case. Tidy up the cables so you can get good airflow to the CPU, and have an exhaust fan to push hot air out of the back of the computer. You shouldn't need anything really fancy, but just make sure that the hot air leaves your computer and the temps should drop. You could also just take the side panel off and run the PC as a temoprary solution. I do this at LAN parties if my computer starts locking up due to high temps...mine hates going into 40c... :(

-Tim_axe

This problem is because the CPU cell that is BIOS cell has grown weaker and u need to change it, as it do not remembers wat was stored in so that is why this is happening . Change the BIOS cell buddy and u will be healthy with ur CPU