Time stops when idling

Hey !
It has been a few days that, everytime i go to sleep or afk, the time stops and I have to set it back when I'm back !
For instance, yesterday i left at 0:12am and today the time was stuck at 00:50 or something like that. So what I did is go to time settings to uncheck then check again the "set automatically" button.
I don't know what to do, I already tried to completely reset my pc but it didn't change anything to that problem ..
Do you have any ideas ?

I hope my english is not so confused

Bad MB/BIOS battery?

CountryBumkin said:

Bad MB/BIOS battery?

that shouldn't affect the time when computer is only sleeping

You MIGHT try setting an internet clockto update it. I prefer tick.usno.navy.mil.

They're the ones that keep the atomic clocks. The Windows default clock sucks.

This is a real shot in the dark, but do you have AOL Desktop installed? I installed the latest AOL Desktop on my WIN 7 pc and it affected the Windows clock. I rolled AOL back to a prior version and the clock worked fine again