Help! Something Eating My C Drive

I have a problem i never had this happen before but yesterday i noticed that when i went into my computer and saw that the C drive had 156GB free space (i have a 500GB Hardrive i partitioned the drive into 2 separate ones C and F)now My C drive Says this 0bytes free of 244 GB, my F drive is fine nothing wrong still shows 219 free of 221GB, but yesterday i left the house everything was fine with the c drive when i left and came back and it said low drive space it went to ZERO!! from 156GB in about 2 hours and im soo confused what happened?? i had nothing installed that could do this, i ran Norton on it it didn't pick up anything i ran Malwarebytes on it and it didn't resolve the issue i also ran registry mechanic on it and that still didn't resolve the issue, now here is where it gets real interesting i restarted my computer and the drive space came back! but now its slowly decreasing again! and i tried this over and over again and it keeps doing it its like something is eating it slowly every time it gets more space free up and now its back at 0bytes free of 244GB i need help on how to resolve this issue i have windows 7 home premium 64bit

I dont think i have any backup programs installed and system restore i dont think so how do i check?

it says i have no restore points created

ok i turned off the restore settings now what?

ok i turned the C drive back on for restore