hi, i'm not sure my opinion is useful of not,.
but first, i can definately tell you that the picture of that 750 processor is 478 MIcro-Pins. (dothan)
TS mentioned that it's not working on his motherboard.

perhaps TS need to tell me what motherboard.

if you are using a plateform supporting 533Mhz, i think the processor will work fine.
the Code name of the Sonoma platform motherboard is 915. (mobile platform)
The older platform supporting Dothan is coded 855. (support up to 400mhz)

To make it simple :

750 should work fine on 915 platform
Certain 750 doesn't works on 855 platform because of bus speed incompatibility.

TS nvr mentioned about the motherboard he is using...
i not sure why. If he just can tell me what Motherboard he is using, then immediately this arguement comes to an end.

Ong did provide sufficient information about the processor. Should be working fine on any 915 platform no matter what voltage it is. TS should have know this since he "claims" to have so many years of experience.
However, if TS using any other motherboard than 915... and the processor is not working, it's buyer's responsibility and not the seller.
If TS is using 915 platform and the processor is not working, then i think, Ong, you have to check the processor.

in the end, i support Ong , not because he's been here for many years.
Because Buyer, you didn't check the properties properly before you buy.
u should have ask about the previous motherboard that this processor was on. (what laptop and models taken from). then immediately you can guess whether it works on your laptop or not.

what i believe is that caspian's customer laptop might be using 855GM platform, running on Pentium M 400FSB.
Caspian might have tot that this motherboard would support 533FSB chip, thus he got this chip from you..and ended up here...haha..

he says he is 15 years, then i should be 21 years experience because i started putting up computers since the age of 6...hahhaa...i still remember how i screwed with my father's apple 8088...