I have a Dell XPS 4435MT desktop. It randomly freezes – and it happens shortly after startup, mostly less than 10 minutes.
When it freezes, mouse and keyboard have no power anymore. The USB ports on the front and back do not have power until reboot. Upon reboot it will normally work until a normal shut down.
It’s really a hit-and-miss situation after start up. It seems like Article 54401 on Dell’s support site covers this. My chipset is different at Intel ICH10 family though.
All Chipsets have that safety feature to cut power to usb port(s) when there is a current overdraw, usually it only shuts down the port(s) or hub that has the over current, not all of them.
When they stop working have you unplugged them and moved to other usb ports before you hard shutdown?
What other usb devices are connected when it does this? Disconnect them for testing purposes, a process of elimination as suggested in the Dell article.
Use a different keyboard and mouse, see if the behavior stops.
I would also check the motherboard for bulging or leaking capacitors
I posted the question – not sure how this works but the solution was to replace both the hard drive and the motherboard. Works fine now – expensive fix but the only solution. My Modele is actually a Dell XPS 435t – not 435mt – Thanks for your help