There you sit with the "state-of-the-art" personal computer you bought a few years ago. By now, maybe you've got your eye on high-end software that requires more memory than you have, or you're tired of having to delete files to keep your old hard drive from zeroing out.

In short, you're growing weary of your PC's less-than-state-of-the-art performance. Should you chuck your old reliable for a shiny new machine or try to cobble together a better computer by adding some new parts?That depends on a lot of things, including your budget, your patience, whether you have truly outgrown your current system . . . and how brave you are.

If the computer's central processor needs updating, it's probably best to buy a new machine. Replacing your computer's CPU is a nerve-racking task that may not be worth the trouble, anyway. A new processor can easily cost more than $300 - about a third of what it will cost you to update the entire system.

If there's only one component of your PC that's inadequate, such as the hard drive or random access memory (RAM), and you don't anticipate having to upgrade anything else in the next couple of years, then upgrading might be the best way to go.

Assuming you install the additional component yourself, 32 megabytes of RAM will cost you between $70 and $280, depending on which type of memory your computer will accept. A 3.2-gigabyte hard drive will set you back $180 to $240.

If you're squeamish about popping the lid of your PC and plugging in new parts, you can pay a local consultant or hardware dealer to do it for you. RAM upgrades are fairly straightforward and shouldn't take more than 15 to 30 minutes, assuming there are no problems. Some places charge nothing for installation as long as you buy the part from them; others charge up to $40 for labor.