Help! Lockup Problems!

[gthorn2000]

My parent's Dell 8250 occassionally locks up after sitting idle for over an hour or so. I ran diagnostics and there is nothing wrong with the HD or any other hardware. I also uninstalled all unnecessary software. What could be causing the PC to lock up?

 

[4keatimj]

What are the specs of the machine?

Do a check for virus/spyware, check the task Manager to see if there are any programs running that shouldn't be. Also, check your Power Options in the Control Panel. Some PCs, especially pre-made ones (HP and Compaqs seem to be the worst offenders) don't always turn back on if the monitor or hard drive shuts down after a certain amount of idle time, nor do they always wake up if they are in Stand By mode. This is a hardware/software incompatibility of sorts, the only way to make it stop is by disabling them from happening in Windows.