Ignorance is only a problem when somone refuses to acknowledge it. LOL
Regarding the memory modules, it all depends on what type they are. there are various kinds (simm, dimm, etc) the best way to find out would be to visually compare the two, or compare the slot to the module. If it looks the same, try it. You're 'NOT LIKELY' to cause any damage. . . If it's not compatible, then it just won't work. just remember the following things
1 you should earth yourself BEFORE handling memory modules (and frequently whilst handling them) as they're ESD sensitive (ideally you should use an earthing wrist strap)
2 DO NOT try and force it, if it looks different, IT WON'T work (check they have the same number of pins)
3 If you're not sure what to do, I recommend going to a computer forum for further advice, or go to your local computer repair shop (though their advice is usually NOT FREE)
4 Compaq computers can be very 'FUSSY' about which memory or other cards will work.