midi keyboard not playin sounds??

[jamesarmstrong]

i updated to 8,2,7 a week ago and its been fine but for some reason out of the blue i cant play synth sounds on my midi keyboard or the qwerty keyboard 1 in 10 or so presses registers but the sound continues long after i releaesed me finger and its not the release on the preset.the midi is all connected and it flashes in the cornerwen i press a key it just wont play.everything worked fine ubtil last night and i cant understand why its playin up all of a sudden,i loaded up 8,2,1 and it worked i even uninstalled 8,2,7 and reinstalled the update but still doin it.any ideas?