I am installing more memory.I have 64 now.Only thing locally for pc100 is a 128 stick.Do I only put that in or do I use them both to make 192?Also,which one goes in slot one,the 128 or the 64.Have read different opinions on this.I can also get a pc100 64mb on Ebay.Am I better to go with another 64?

It shouldn't make any difference what slot the memory goes in. There's no problem with you leaving the 64 where it is,and putting the 128 next door, for a total of 192. (Just did this exact thing at my brother's house!)

It is always safer to use a Memory Configurator from a reputable Memory Vendor like Crucial before buying the RAM If you plug in the relevant data (like the Make& Model of your Brand name PC or the Mother board in your Custom Built PC in the Memory Configurator's Fields, you can find the Exact type of RAM , the Maximum your PC can hold etc. You may also find an illustrated manual of how to install RAM from links in that site. Other sites giving similar help include: Kingston Memory Configurator Memorystock Computer Memory Upgrade Configurator

MaadhuriMN you are right, if someone isn't sure what kind of memory to get for their machine, then by all means go to a site like crucial.com. But in this case, a Pent 2 400, it's a slam dunk that PC100 is what he needs.

raincheck, Generally speaking, I agree with the rule of thumb you have suggested. As you may know, in the case of some Brand Name PCs this may not always work. To illustrate the point, let me give the examples of two PCs with PII 400MHz. 1.Compaq ProLiant 1600 PII 400 MHz Memory SDRAM, PC100 CL=2 • ECC • Registered 2.Dell DimensionV400 PII-400MHz PC100 • CL=2 • Non-parity Knowing the exact make & model of the Mother Board makes RAM upgrade decision a lot easier.