usb mouse freezes kde on boot

Any ideas why having a usb mouse plugged in on boot freezes up KDE
(that's all I can tell as a noob, no mouse/keyboard, mouse icon stuck
as pointer + devil icon, and no disk acess).  However, if I boot then
plug in the usb mouse, no freeze, and it works fine.  Bsd being what
it is, I assume there is some method of recovery from a frozen KDE?  I
tried ctl-alt-del, of course, but no avail.

Best,
Steve