I've had a strange problem with my x41t, Windows XP SP 2, for a while now and after much searching I'm stumped. Maybe someone here can see what's going on.
A little while after a reboot (within a day?), the browser back/forward buttons, the hardware volume buttons on screen display, and the ctrl-alt-del combination stops working.
The hardware volume buttons still control volume, but the on screen display stops showing up.
The alt-left-arrow and -right-arrow combination still works for back/forward in the browser and file explorer, but the dedicated back/forward buttons stop working.
Sometimes maximised windows will cover the task bar (which is set to always be on top). Sometimes this problem fixes itself. Sometimes maxed windows will cover the bar, and then when I click in my second monitor extended desktop, the task bar on the laptop will reappear. Then when I click back on the laptop, the window hides the task bar again.
There definitely could be several problems here all working at once.
Restarting TPHKMGR tends to fix the volume button on screen display problem temporarily.
Only a reboot returns things to normal.