My Harddisk Space going Somewhere [HELP]

[melev2910]

Hi Guys, I use my WDC blue with normal uses. It display that it just have 11GB space from my 100GB Drive C.
But when i Go to my C and I Properties all Folder it's just 60GB Used, so I must be have up to 30GB space or more. I use Baidu PC Faster to clean my Junk. I use Avast AV to scan for viruses.But No problem founds. Every I update my Nvidia driver my Space on C reduce up to 1gb every Update. But Drive D Clean from this problem.
Even The Performance got no problem, the disk space from my C reduce too much.
May be u Guys can help me.

Thx Before

 

[USAFRet]

1. WinDirStat to visualize where you space is
2. Some things do not appear in that. System Restore points, for instance.

 

[melev2910]

Thx sir, I force to use the system restore my C to 1st state after i install all my drive, hope next time not meet with this problem again