PC won´t stay in Sleep Mode

When i put my pc in sleep mode it wakes itself up almost inmediatly a couple of seconds later only to sleep itself again and then wake up,it stays in this cycle indefinitely or atleast untlil i press a button to wake it up.
This Started to happen after i upgraded to V5.
PC
AMD Phenom II X4 945
8 GB RAM
ATI HD 5450
OS Windows 7 Home Premium 64 bit.

Any idea what could be causing this?

 

bump in case it wasn´t noticed before.
hopefully somebody can help me with this issue.

 

From a CMD prompt run the command:

Code:

powercfg -lastwake

This might tell you what caused the last wake of your computer. Most likely it will be one of your USB devices and not ESS, but you never know.

 

@rockshox Tried it after pc woke up and it showed the number of times that the pc woke up but not the cause (no devices listed).
Any other ideas?.

 

If your computer is compuiter is connected to the internet via a LAN cable try going in to the Device Manager and choose your LAN card and switch off `Allow this device to wake the computer' under Power Management.
Similarily, if you have a fax modem in your computer connected to the phone line you might have to do the same.
If you are only on Wifi then it is probably a software issue. It could be a disk defragger thatb waits for no ativity before degragging the harrdive as an example

 

@buckshee Thanks,that fixed it altough it´s kinda weird that the problem was the LAN card because i have almost a year with this pc and i didn´t have this problem until recently that´s why i thought it was ESS fault being that the problem started after i upgraded it.