I had a somewhat similar problem with this desktop.
It would run with PC2100 in one slot and PC3200 in the other...but I could not run two modules of PC3200 (even though they are the same specs).
After experimenting (and running Memtest on the RAM modules), I figured out that the system was fine only when I used the "slower" memory, which causes the system bus to default to a lower value. So even though the motherboard said that PC3200 would work...the motherboard preferred PC 2700 or PC2100.
So I adjusted my BIOS RAM bus...from 200 to 166 (400MHz to 333MHz) and the system has been running without errors, etc. since, using the PC4200. An underclock
Your situation seems analogous but you also have to check out your RAM sockets on the motherboard, they can go bad or be dirty.
I would suggest taking a look at the manual for that laptop and see what real recommended RAM speed is. From what I see, "DDR2" is not going to cut it...since all DDR2 is not equal in the eyes of motherboards.
I'd also contact Crucial and see if they have an answer for what you've experienced, especially so if they said the memory you bought would work fine in your system.