Monitor goes to sleep can only reboot

[Steve]

I have a new Hp desktop with a lcd monitor and a new toshiba laptop satelite,
both running VISTA. Both have the same problem, Intermittently the Monitor
goes to sleep on the HP, and Justs turns black on the Toshiba, In both cases
the systems has to be RESET! You can here the programs running, but cannot
get the monitor to come back. My guess is when an application attempts to
change screen resolution this happens. On the Hp I tried to download a new
monitor driver and all I get is "ACCESS DENIED" when it tries to install.
Both systems were purchased with VISTA on them. Somebody please help.

 

[Net Doe]

Did you try pressing fn+f4 to get the displays back? Are you installing the
updates from an admin account?

 

[Steve]

Yes tried the update with Administrator, have not tried the function F4 will
do when it happens and let u know