My PC goes on sleep mode on its own; and it is set to never do so. Can anyone help me please?

[Its a me]

When ever i leave my computer on and go for some time, it starts the sleep mode. This is specially anoying when i leave a game downloading on Steam because they take forever. Anyone have any clue of whats wrong?

 

[brarboy]

if you want to turn off sleep mode, go to:
Control Panel > Power Option > In the Left panel click on "Change when the computer sleeps" > Under Put the computer to sleep: Never
If that doesn't solve your problem, on the same page click "Change Advanced Power Settings", under Hard disk and Sleep options make sure they are set to 'Never'.