wuz up i have been using cubase 5 latest update i think it 5,5,2 . i have a pc computer with 2 hard drives and 4gb using vista and my sound card is m audio fast track ultra. i recently ran into a problem where my midi notes sound completely different then when i play them in my motif. it sounds like a lil distorted. i never had this problem before. it just came out of no where. i uncheck the midi thru in the prefreneces and this still continues . i used to jus un click that and problem would be gone. now it stays around. this makes it hard to edit midi notes because they sound nothing like how the motif sounds. i NORMALLY record a midi track and then once i like the midi i record it to audio. i noticed im seeing after touch but even when i draw the after touch notes down i still get that distored sound. HELP. THANKS IN ADVANCE FOR WHO EVER RESPONDS
By your description, it sounds as if you have an AUDIO problem, not a MIDI glitch.
If you can record and edit your MIDI events normally, but the sound is distorted, I would look to your audio drivers. Just guessing for the moment. Is it just your MIDI tracks (ALL of them) that are distorted? just recent tracks? more info would help. 
check your ASIO settings .