PC333 RAM Problem ?

[MaMister]

Hi, I have a pc with 128MB PC266 DDR RAM. Using Win98.
Went get a piece of 256MB PC333 DDR yesterday.
Plug in the RAM, can boot and see in bios 384MB but window protection error.
Put 1 RAM at a time, no such problem.
Try long time last nite, finally give up. Use the new 256MB instead.
But yesterday shop keeper says the new one will work fine with my old one.
Shop close today....can't get help.
What's the problem?

 

[mechBgon]

The more information you can give about the parts in the computer, the better we can help, so tell us whatever you know about the brands and models of the parts. In particular, if you can give the brand and model of the motherboard?