To quote MicroSoft; Q329284: http://support.microsoft.com/kb/329284
"A machine check exception occurs when Windows XP and your hardware platform cannot recover from a hardware error so that the system can continue to run successfully and reliably. More specific diagnosis of machine check exceptions is difficult, and there is no general solution. Contact your hardware manufacturer or a computer hardware technician for help with troubleshooting this issue.
Machine check exceptions are frequently caused by one of the following conditions:
* You are running the processor or mainboard beyond its specifications. For example, you are overclocking the processor or bus. We recommend that you run your hardware at the manufacturer-rated speeds.
* Noisy power, overstressed power strips, outmatched power supplies and failing power supplies can destabilize your computer. Make sure that you have a stable, reliable power supply to your computer.
* Extreme thermal conditions caused by the failure of cooling devices such as fans may damage your computer. Make sure that your cooling devices are all working.
* You have damaged memory or memory that is not the correct type for your computer. If you recently changed the memory configuration, revert to the previous configuration to determine what is wrong. Make sure that you are using the correct memory for your computer."
I must make a post or be deregistered. I have used this, excellent, site for information and troubleshooting purposes. I have not felt competent to make any posts to assist others yet but I will try to contribute when I can.