Your processor is most definetly a candidate to be overclocked...DON'T let Mr. Rigoletto burst your bubble so fast...
for about $50 you can overclock your athlon. All you need is a GFD (Gold finger device)..they run about $20 now. Then you will need a good Heatsink and fan..I would recommend the Alpha P7125, which will run about $30. If you goto this site:
Overclocking Basics, it will give you a good run down of what has to be done to overclock your athlon, by the way do not be intimidated by the removal of the plastic case surrounding the CPU. The removal actually will keep your CPU cooler.
Another factor as to why you might overclock..Odds are that your Athlon 700 is actually higher than that...but you can't tell for sure unless you rip off the heatplate ( I wouldn't do that yet)..AMD usually puts higher rated cpu's in then underclocks them.
Anyway ..good luck..if you need anymore assistance let me know..