dude this could be your problem
SYMPTOMS
When you attempt to resume your computer from Standby mode, the computer may not wake up.
CAUSE
This behavior can occur if the following two conditions both exist:
• Advanced Power Management (APM) is enabled in the Power Options tool in Control Panel.
• Your computer's BIOS is configured to suspend your computer and the time-out value is less than the value configured in the Power Options tool in Control Panel.
RESOLUTION
To resolve this issue, configure the time-out settings in the Power Options tool in Control Panel so that they are for a shorter time than the APM time-out settings in your computer's BIOS. To view or modify these settings in Control Panel, click Start, point to Settings, click Control Panel, and then double-click Power Options.