Question PC shuts down instead of entering sleep mode ?

[imspiffy]

Every time I try to put my pc into sleep mode, it just shuts down instead. Also it doesn't shut down instantly but it takes a couple minutes to do so. I am not sure if its a hardware issue or software, but I've been having this problem for quite some time. I tried adjusting some power settings and nothing. Even tried going into BIOS to see if I can find anything there but I'm not sure what I'd be looking for. Does anyone know what might be the issue?