PC memory - Compaq Dekspro PII 400MHz

[mxroadster]

I need to buy some memory for a friends PC and she's clueless and can't be persuaded to lift the lid and look inside for me. She has a Compaq Deskpro EN 400/100 with the PII 400 chip. Currently only has 32Mb which is probably all in 1 DIMM.

Quick check on Compaq's website puts this as a motherboard with 3 slots for DIMM's but tracking down whether I need PC64 or PC100 memory is the problem. If I just buy PC100 will it work anyway or does it have to be correct? It also says it has to be CL2 or CL3 - isn't all memory like this anyway? I want to buy it in advance and take it with me to install rather than looking at what's installed before ordering.

Anyone know the cheapest source for 256Mb of Ram for her PC?

Thanks for any info.

MX