Trying to enable the “Hybrid Sleep” feature in Vista and are simply unable to locate the “Allow hybrid sleep” option under the Advanced Settings tab of the Power Options box? You can try using the “powercfg.exe -a” command in command prompt to list the number of power states. However if you have tried using this step and have come face to face with an output such as
“The system Your browser may not support display of this image. Or firmware does not support this standby state: Hybrid Sleep”, then you can try using some simple resolution steps.
Sometimes the problem can be fixed by simply restarting the computer. This allows the Hybrid Sleep option to reappear under the Advanced Settings tab and also displays the sleep state when the powercfg.exe -a command is run. However in certain cases the problem is rooted in much more complicated causes.
A possible cause for the missing Hybrid Sleep function in Vista could be inability of the BIOS or the motherboard in supporting ACPI S3 sleep/standby state. While most ACPI compliant hardware do not face this problem, certain motherboard BIOS provide the users the facility to choose the suspend type or state S0, S1, S2, S3, S4, S5 to be implemented. Most of the times the S1 power state is implemented as the default power state. To find the Hybrid Sleep state restart the computer and boot into the BIOS to check the default suspend support. Now change the suspend state to S3 which is STR or the “Suspend to RAM” state to enable the Hybrid Sleep option.
The problem can also be attributed to a race condition existing between the Monitor.sys driver and a kernel setting. This can be corrected by using a supported hotfix available from Microsoft. You can contact Microsoft Customer Service and Support to obtain the hotfix or downloaded it