I had partitioned ~65 GB of space on my HDD for Win7, and data on the other partition. That worked fine for couple years. Then one day, when I tried to update Flash player, it failed due to low disk space. Don't recall how much space I had at the time, just that C: drive capacity had been hovering in the red zone. I deleted couple restore points and system error dump files to free up space. Eventually, I installed a 250 GB SSD for the OS. After deleting Win7 partition on the HDD, I got more room for data.