instrument cluster board damage is all i can think of... to reset the odometer, all it should take is a forefinger push for at least 2-5seconds, and you're done.
If there is no response, then, you possibiliites are:
1) the contacts of the reset button are corroded;
2) the program on your instrument panel is corrupted;
3) you are not pushing the right button; or,
4) (if you are not the original owner) it's possible that the odometer has been previously tampered with...
__________________ ay sino caddi ububblaem?   Heaven won't take me; and Hell just knows I'll take over...! | 
