Hey Rajesh,
Check that Hibernation Mode is Enabled First and then Reply.
To Do This (If you don't know already):
1. Go To Start>Control Panel>Performance and Maitenance>Power Options
2. Go to the Hibernate Tab
3. Make Sure that the "Enable Hibernation" Checkbox is Ticked.
Please Reply and tell me if that helped,
Nathan.
Rajesh,
If Natan's suggestion doesn't fix the problem, take a read at this
(from Microsoft):
How to determine whether a computer is using ACPI features:
Hibernation and standby require a system BIOS that supports ACPI or
the former Advanced Power Management (APM) specification. To avoid
problems, review system documentation or see the manufacturer's Web
site for information about how to determine whether the firmware is
compliant and up to date. Updated firmware is especially important
when you use the ACPI functionality.
To determine whether a computer is using ACPI features, follow these
steps:
1. Click Start, click Run, type devmgmt.msc, and then click OK.
2. In the Device Manager window, expand Computer, and then verify
whether you can see the Advanced Configuration and Power Interface
(ACPI) PC option. If you can see it, the computer is using the ACPI
functionality.
How to determine whether a computer supports hibernation and standby
features
1. Click Start, click Run, type powercfg.cpl, and then click OK.
2. In the Power Options Properties dialog box, verify that a Hibernate
tab exists. If the tab exists, click the Hibernate tab, click to
select the Enable hibernation check box, and then click Apply.
3. In the Power buttons section, verify that the Standby option and
the Hibernate option appear in the drop-down list on the Advanced tab.
Note If a Hibernate tab exists and you click to clear the Enable
hibernation check box on the Hibernate tab, the Hibernate option will
not appear in the down-down list on the Advanced tab.
If both the Standby option and the Hibernate option do not appear,
either the computer does not support these features or the power
management features are disabled in the BIOS. Contact the system
manufacturer for information about the BIOS settings.
Added:
Or enter the BIOS in your computer and check what options you have.