HOW TO SPICE UP THAT OLD SYSTEM
One of the most important things to upgrade is the processor. Unfortunately, this can also result in being forced to upgrade the RAM and the motherboard as well. Right now, the best price/performance ratio is in Intel's Celeron line of processors. They are cheap, powerful, and some are very overclockable. The older Celeron's require a Slot 1 motherboard need a Socket-370 motherboard. If you have a Slot 1 motherboard but a socket-370 processor, don't despair! There are kits available to convert the -370 celerons to a Slot 1 configuration. If you have a Socket 7 motherboard that you don't want to get rid of, then your best bet is an AMD processor.
I would recommend just about any ABIT motherboard (especially the BX6r2) because of their ability to overclock and manipulate voltage settings from the bios instead if jumpers or dip switches. A good processor choice is a celeron 300a overclocked to 450mhz. I have one of these and for a $60 dollar chip and $100 dollar motherboard it's hard to beat. Newer on the scene is the celeron 366. Early versions of this chip are not very overclockable but chips manufactured since June have been reported as being very overclockable. There is a very good chance of getting 550mhz or maybe even 600! If you're going the Socket 7 route, the best idea would be for a the fastest K6-3 you can afford.
There has been a lot of controversy over how much RAM is needed in a system. I'm no expert on it, but from what I've read , there's only a 4%-6% perfomance increase between 64 and 128 megs of RAM. A jump to 256 give almost no increase. Of course, RAM is getting very cheap these days, so buy whatever you can afford. Make sure to get at least PC-100 ram so that overclocking is not a problem. PC-133 is now becoming available but is still quite expensive.