I have a PII350, 192 PC100 RAM on a BX MotherBoard. What is the fastest CPU I can install on the above, or would it be cheaper just to buy a new faster pc? Because if I am correct, a faster CPU will need PC133 RAM also and that would be another expense than just upgrading the CPU. Please advise.
You'll have to find out what BX board that is, then you can look it up on the manufacturer's website. Many of the processors today are fine with PC100 SDRAM, so you don't need to worry much about that.