Try the following
(1) Check if allow this device to wake the computer is checked in Device Manager.
1. Click Start, type Device manager in the Start search box and hit Enter.
2. Select keyboard, it will display your keyboard, right click and select ‘Properties’.
3. Select the ‘Power management’ tab.
4. Check the “Allow this device to wake the computer†check box.
Repeat the above steps for Mouse, too, and restart the computer and check if that fixes the issue.
Also, just to be double sure you have the latest drivers; you may check by visiting the manufacturer’s website and confirm the same.
(2) You may also create a power plan and customize the same. A power plan is a collection of hardware and system settings that manages how your computer uses and conserves power. Power plans can save energy, maximize system performance, or balance energy conservation with performance.
Refer the link below for more details on Power plan:
Change, create, or delete a power plan (scheme)
http://windows.microsoft.com/en-US/windows7/Change-create-or-delete-a-power-plan-scheme
(3) You may also run the Power troubleshooter to adjust your computer's power settings. The Power troubleshooter checks things like your computer's timeout settings, which determine how long the computer waits before turning off the monitor display or entering sleep mode. Adjusting these settings can help you conserve power and extend your computer's battery life.
Refer the link below for more details:
Open the Power troubleshooter
http://windows.microsoft.com/en-US/windows7/Open-the-Power-troubleshooter
(4) Try disabling the security software temporarily if that is causing the conflict.
(5) You can also try updating the BIOS, for that you can contact the BIOS manufacturer.
Excerpt taken from following link
Code:
http://answers.microsoft.com/en-us/windows/forum/windows_7-system/computer-freezes-shortly-after-waking-from-sleep/97f9a34d-f82a-49f5-9924-4be34ffcae75