Question : Problem: System Crash on Boot following RAM Upgrade

I have a desktop PC with an Epox EP-4SGM8I  motherboard (2.60 gigahertz Intel Celeron 8 kilobyte primary memory cache 128 kilobyte secondary memory cache) running Windows XP Professional Service Pack 3 (build 2600).
I am attempting to upgrade my RAM from 512MB (2X256 modules) to 2GB using  Corsair VS2GBKIT400C3. When I install both modules from VS2GBKIT400C3  and boot my PC crashes with blue screen just prior to log on screen being displayed (crash occurs too quickly to allow viewing of error messages on blue screen)
If i remove either of the new 1GB modules and replace with 1 of the old 256MB (so one 256 and 1 1GB installed) modules sytem boots correctly and indicates 1.25GB of funtioning RAM
If i install just the 1GB singularly PC boots with no Error
i have contacted Corsair support who offer to replace my new RAM but also comment "We can try replacing the memory for you, but if you only have problems when running them together, there may be a problem with the memory controller on the motherboard and a new set of memory would not resolve the problem.  If possible I would suggest testing the modules in a different system to see if you can duplicate the issue.  With the 1GB modules there will be more stress on the memory controller than with the 256MB modules and that may explain why the 256MB memory is working while you are having problems with the 1GB modules"
Is there a method of testing or configuring memory controller, is there any other thing i should look at ?

Answer : Problem: System Crash on Boot following RAM Upgrade

You can try under clocking memory bus and therefore memory speed in BIOS. Reduce memory bus speed to 166MHz and see if memory stabilizes.