I recently made the move from Windows XP to Windows 7. Since then, when my computer is on for a few hours it always ends up rebooting without warning. Then the BIOS won't recognize my hard drive (hard drive 0 not found).

If I turn off my computer and then on again, it boots normally.

Some details:

• Dell Dimension 9150
• Windows 7
• I updated the BIOS
• I updated all system drivers with the latest version from Dell (SATA, Chipset, etc.)
• Other drivers updated too (Graphic card, sound, etc.)

There is one thing that I tried after some Googling: I turned off the DMA access to the drives, but it's still rebooting after a few hours.

Any clue?

UPDATE 2010/12/13

Here are the events from the Event Log for today, from when I turned the computer on until it crashed:

19:17 - Error - ID 10016 - DistributedCom

20:06 - Error - ID 1008 - Customer Improvement Program (could not send data to Microsoft)

21:48 - Critical - ID 41 - Kernel-Power (System was restarted without proper shutdown)

21:48 - Error - ID 6008 - EventLog (Previous system down was not planned)

21:48 - Error - ID 1101 - EventLog (Audit Event ignored)

21:49 - Error - ID 10016 - DistributedCom

Both DistributedCom events have a description along these lines (translated from French):

The authorisation parameters specific to the application are not allowing Local Execeution for the COM server application with the CLSID {C97FCC79-E628-407D-AE68-A06AD6D8B4D1} and the APPID {344ED43D-D086-4961-86A6-1106F4ACAD9B} to the SID AUTHORITY NT\User System (S-1-5-18) from the address LocalHost (LRPC usage). This security authorisation can be changed with the Component service administration tool.

UPDATE 2010/12/31

Here are the error messages I have on blue screens : STOP C000007xA - Kernel_Data_Inpage_Error "Unkown hard error" C00000135 - Can't start because &hs is missing