waking computer with PS/2 keyboard?

Windows 7 64bit.
I had a Microsoft wireless keyboard/mouse combo installed. Reception was terrible so I got a wired keyboard (PS/2) and wired mouse (USB). I used to be able to start my computer in the morning just by pressing the SPACE key. I'm not able to with the new keyboard, also moving the mouse doesn't do anything. I have to press a mouse button to wake it.
I didn't change any settings in Windows or in the BIOS.
There is also no "power options" tab in keyboard properties.

Am I missing something?
I just want to be able to sit down and press the space key.

Sorry, nothing to offer as a solution. I'm actually having a similar problem. I have 4 identical computers except for the after market coolers. 3 of these PCs will wake by simply moving the mouse, one will not. The only way to wake this rogue PC is to press the power button, so if you find a solution, would sure appreciate if you could post it, if the answer does not come from these forums. thanks

The answer may lie in your BIOS in many cases... for example mine contains the options for wake on LAN, PS/2, etc... and the settings in the BIOS take precedence over Windows power settings...

I don't see any settings for a PS/2 keyboard in the BIOS of my computer.
EVGA SLI3 motherboard with latest BIOS.

I said "may" as it is entirely subjective, as each board has different options... sometimes you need to hunt around to find some settings too...

I'm not sure if it helps but it isn't a Windows setting that changed it. Windows isn't loaded yet so it has no effect on this function. Just to be clear, I'm talking about boot up from an off state not waking up from hibernation. On my ASUS motherboards its a jumper setting and a BIOS setting. I have to move a jumper on the motherboard to feed the AUX +5V to the PS2 ports. Then I have to change a setting in the BIOS to allow power up when the keyboard or mouse is pressed. Also even though the same jumper feeds the AUX +5V to my USB ports a USB keyboard or mouse won't power up the PC. The one you press the button on has to be on a PS2 port. I haven't used that function for a while and can't remember if moving the mouse was enough.

OK, yeah if waking from sleep S1 or S3 state the Windows power options likely have an effect on things. At least you can actually get your PC to come back out of sleep mode. More often than not when I try it nothing ever happens and I have to resort to hitting the reset or power button. Sorry I can't be more help but I gave up trying to get it to work reliably ages ago.

About a month ago I had this problem. Suddenly the computer would not wake from sleep mode
using the PS/2 keyboard.

The solution for me was to uninstall the keyboard through device manager and then
follow the prompts through the reboot processes to automatically reinstall the keyboard
as a "found new hardware" device.
After the first reboot, a prompt appeared asking for another reboot to complete the process.

That fixed the problem.