Windows 7 x64
I have checked the task scheduler and I don't see anything that is scheduled to run during that time frame.
I have watched the task manager during the slow period and nothing it taking up much resources that would explain the slowness.
I have reviewed the event viewer and have found loads of nvstor64 event id 3 errors during that period. It turns out that this error occurs at other parts of the day but the user isn't at the computer during those times. The user has had the PC for a year but only noticed this problem more recently.
event id 3
Data error on device.
Device: \Device\RaidPort0 Model: WDC WD800AAJS-60B4A0 Firmware Version: 02.0 Serial Number: XXXXXXXX Port: 0
HP doesn't offer Windows 7 x64 drivers for this PC.