BSOD

Hardware Malfunction
Call your hardware vendor for support
NMI: Parity Check / Memory Parity Error
The System Has Halted.

We need more information from you; specifically your make and model of your motherboard and how much and type of RAM you have installed.

You mention BSOD but what code was written on the screen? For example 0x00000050: PAGE_FAULT_IN_NONPAGED_AREA and often, but not always, followed by a driver like vsdatant.sys or nv4_disp.dll.

A parity error was detected within the system memory. Parity checking is used to detect memory corruption between the time that data is written to memory and the time that it is read back.This error message means that there is a problem associated with the system memory. Depending on the system, you may be told some specifics about what part of memory caused the error.

Diagnosis: There are many possible causes of memory parity errors, some of them only related indirectly to the memory, or even having nothing to do with the memory at all. In particular, a memory error at start up is often indicative of a wide variety of possible problems.

It was not a true BSOD it was blue and had the typed message showing.
I have a Dell E1705 Laptop with 1.66 Core Duo processor
Not sure of the mobo but has integrated graphics think it was only one mobo used for that. Service tag is 7N20S91 if you can look up what you are needing. I upgraded a few months ago to Crucial 2GB (2 1GB sticks) PC2 5300 667.
I also just upgraded hard drive to Hitachi Travelstar 5K320 250GB. The parity error occurs at random had it 2 times in as many weeks. Always after computer has been sitting for a while idle not during peak usage (yet).

Do you know how to access your BIOS and can you tell us what timings and voltage your motherboard has your memory set at?

Yup will check when get home and take a look.