If i leave sleep mode in windows 8.1 my cpu fan (FX-6300) stops or barely spins at all! Any solutions?
The CPU goes into an ultra low power mode when in Sleep mode. Don't worry it's normal.
stops in sleep mode = design
spins slowly when cpu is cold = design
if it's doing either of those things you're ok
if it's barely spinning and your cpu is overheating you have a dying cpu fan and need to replace it ASAP. download HWMonitor. put your pc into sleepmode while hardware monitor is running. wake your pc, and check out what it is reporting is your cpu temps and cpu fan speed.
yikes.
what is the socket temp on your motherboard? are you 100% certain your cpu temps are accurate? (the socket temp should be +10C hotter then the cpu temp)
yikes... try updating your motherboard's bios. that might be a bios bug with that motherboard. if that doesn't fix it i would turn off quiet and cool in the bios. see if that stops it. if that doesn't work you might have to consider the possibility the cpu fan is dying.