Sleep now works perfectly after a small tweak on GA-G31M-ES2L(BIOS ver F10).
All that we have to do is place a copy of SleepEnabler.kext under the root of the snow leopard installation drive(/) and another copy under /Extra/Extensions. Repair the drives permission . Reboot and all is fine as a normal MAc machine.
Thanx to insanelymac community for all the articles so far. Keep it up !!

Note: No need to use PleaseSleep utility any more