I ordered 2 (2GB) sticks from them that said they were compatible. However upon installation (which in the past.....for me anyway.....has been a very easy install) my notebook will not boot. I get the blue screen of death. I just called Crucial and now they tell me my notebooks max memoty is 2GB.
Here, they at least give you the speed. From the (Downloadable) User Manual it states:
2 customer-accessible/upgradable memory module slots
Supports dual-channel memory
Supports up to 2 GB of system RAM
PC2-5300, 667-MHz, DDR2
It is good to know what would happen if I over-upgaded the memory. But, there really is no solution to your problem, unfortunately. The vendor should, however, exchange the memory for you.
I just ran across your post looking for XP Driver Support so I'll probably not be back here to followup. Good luck.