Good luckThunder_scream said:try this programmer ... It work for me... and its really in expensive..
you can use ic-prog to program your 16F84
and for more info on 16F84 go to this page
tommyc2000 said:it's not the crystal, it's probably the serial communication between the computer and the programmer
i used my pic16c84-04 with 10, 14.318, and EVEN 16 MHZ crystals and they were working fine, i would assume that pic16f84-04's would work as well with 10 or so MHZ crystals
p.s. the pic16f84a-20 can even handle speeds upto 25 MHZ
(verified by me)