Does anyone know why my PC goes into sleep mode if I leave it a few hours when I'm using a power plan that has Turn off Display and Put Computer to Sleep both set to Never? I've checked all the power plan settings and none of them are set to put the PC into sleep mode yet tonight and yesterday my PC went into sleep mode after around 2-3 hours of non-use while I was using my iPad 4. When I signed back in the browser and webpage were exactly as I'd left it so it was definitely in sleep mode. This issue only seems to have occurred since I built my current Haswell system so I'm wondering if there's a BIOS setting that is overriding the Windows power plan. The odd thing is that I have often left downloading overnight with the Ribbons screensaver running - that's 6-8 hours - yet my PC does NOT go into sleep mode. I really don't understand this. It's not a big deal, I guess, but I'm just confused as to why it is going into sleep mode in the first place. Anyone?