new user w/record/playback noise

[dusty6459]

new user and haven't finished reading the 600 page manuals - would appreciate any assistance. have mbox, plug electric direct into source one, enable track one to record, if i am on the input side, it sounds great, if i move over to the playback side it has a low warbly, distorted sound. went ahead and recorded but when i play back, i can hear the music along with the noise on playback. when i mess around with the sample level on the playback engine (yeah i've been at least pushing buttons) and cpu usage and it stops for a bit but starts up again. using HP pavilion mx70, 1.4g, 586 ram, creative audigy2 soundcard (do not know if that has any impact) I've also tried running a mic line to an amp, or just vocals - same annoying distortion - almost a phasing echoing sound (like trying to explain the "noise" i hear in my car engine...) only on the playback tho - input sounds clean.
Kelly