Originally Posted by
kompukare
Well, gmstartcontrol will show you the SMART status which is the internal monitoring/log from the drive. Not 100% reliable since no SMART errors do not mean the drive is good but if you do get SMART errors (especially re-allocated sectors or - and this is what I suspect if you have a computer which is strangely slow - seek errors) then you can be pretty certain that the drive is on it's last legs.
Of course, running tests on a dying drive might kill it. So I only advise it if everything's backed up.
If it's not the drive, it could be device which is either going bad or has a bad drive. Process Explorer can give you some hints (generally shows up as high Hardware Interrupts) but finding which device it is, is then a matter of trial an error (disable as much as possible in the BIOS or device manager and see if that cures it, then try to find a better driver or live without that device).