a virus in mpc 500??

greetings, I'm new here as well as to mpc, but love it already; however, I recently plugged my mpc 500 to my computer, and ever since there seems to be a virus inside the mpc, because every so often the sound is overwritten. For example, if i'm working on a drum track the sound of the hi hat overwrites and erases the other tracks; and also (randomly) the sound of some tracks suddenly disappears in play mode. Is that a virus?? how do I know?? How do I fix it??
Thank you for your help.