A good old metronome you can stick in your pocket is still best, but here's one for PC that does some VERY COOL stuff (subdivisions of beats, lots more) and it's
free. If any of you know of other good stuff for computer, speak up!
Get this baby and try it:
Metronome Software - Computer Metronome for Musicians
Notice that you do NOT have to scroll your brains out to move from, say, 60 to 184. Just click on the list of tempi for the speed you want, and it jumps to the middle of that range. E.g., click on "Adante" and it jumps to 92 bpm. From there, there's little scrolling to do for reaching the tempo you want.
Also, check out the options and the "Suite" menu. They have TONS of cool music software.

Kojo