Ultimate: a strange keyboard problem...

whenever I press an uppercase "p" in any program Windows Media opens and
comes to the front... also, the tab key doesn't work..

now both these problems happen INTERMITTENTLY, which means the problem
is not with the keyboard.. every time I reboot it's anybody's guess
whether the tab key will work and whether the uppercase "p" letter will
take me to Windows Media every time I press it instead of typing the
letter "p" or whatever it is supposed to do when I press it...

thank you....