Can't Wake From S3 With Keyboard

My HTPC can go in S3 standby mode successfully. BUT the only way to wake my computer is to press the power button. When i wake it up, it starts where it was before so S3 mode is working. Problem is just waking it up.The weirdest thing is that it USED to work. Around 2 months ago i was waking up my computer with my keyboard and it worked. But i stopped to use this feature, and now that i need it, it isn't working anymore.Oh, also wake-on-LAN isn't working neither. And it also used to be working 2 months ago.

Picture from my BIOS

Device manager -> Keyboard -> Power management
>>> Option "Allow this device to wake computer from standby mode" is checked
>>> Option "allow computer to turn off this device to save energy" is unchecked and greyed out
Device manager -> Network cards -> Realtek PCIe -> Advanced
>>> Wake on pattern match : ACTIVATED
>>> Wake on Magic Packet : ACTIVATED

Can't see it on screenshot but the option "Stop wake on LAN" is DISABLED (i also tryed to turn it on but it doesn't change anything)

"powercfg -devicequery wake_armed" tells me that my keyboard is allowed to wake my computer
"powercfg -a" tells me that S3 mode is supported, but S1 and S2 is disabled (that's normal)

Power configuration :

S1 after : Never
Allow hybrid mode : Yes
S3 mode after : 60 minutes
Allow wake timers : No
Selective USB suspension : Off

My hardware:

AMD A6-3650 APU W/ AMD Radeon 65XX HD / Socket FM1 2.6GHZ 4MB 100W
Gigabyte A75M-D2H
Antec Fusion Remote Black HTPC Case
Seasonic 450w 80+Gold (fanless)
4GB G.SKILL Ripjaws X F3-12800CL9D-4GBXL DDR3-1600
Crucial M4 SSD

Solutions tryed, unsuccessfully:

- resetting BIOS/CMOS
- updating BIOS and all other drivers to latest versions
- disabling all other USB devices
- tryed every single USB slots, with and without USB hubs, usb2 instead of usb3 and vice-versa...
- tryed with two different power supplies
- tryed different keyboards
- tryed mouse instead of keyboard, LAN instead of USB...