Free space missing?

Think of me as an idiot.

I'm not a programmer, or particularly adept at anything computer related besides the basics so please bear with me. I've been using CCleaner and Recuva on Windows 7 for the last two months or so and I've been running into some problems.

I can't be sure which it is, but I do know it's either when I use the Secure delete on Recuva or the delete free space on ccleaner. When I run those features I LOSE free space on my drive. My computer tells me I have MBs left when I was sure I still had a couple gigs of free space. The first time it happened I thought maybe I just wasn't paying enough attention to how much space I had left. But it happened again today, and I'm 99% positive that I had at least 10gbs of free space.

Can someone help me out?

Check your root directory (C:\ usually) for a folder with a lot of random characters (eg. C:\E3df23f23f23f3f\) some times CCleaner forgets to delete its leftovers from WFS

"Free space missing" >> "Wipe free space"

Wipe free space overwrites free space. While its in the process of wiping free space you will notice free space on your drive becoming smaller.

Once the operation has finished all your free space should be returned. If your free space has not been returned, do what Winapp2.ini said.

You should understand what every option does before using it.

I don't know what just happened.

I used ccleaner again (the basic function, to wipe all my web caches, recycle bin, etc.) but this time I set it to its default settings (I had originally tweaked it a bit by unchecking some features that I didn't want it deleting such as my passwords and such) After analyzing, it said it could free 700mb. But by the time it finished I had a whopping 60gbs of free space!!!

Wipe free space overwrites free space. While its in the process of wiping free space you will notice free space on your drive becoming smaller.

Once the operation has finished all your free space should be returned. If your free space has not been returned, do what Winapp2.ini said.

You should understand what every option does before using it.

I'm aware of what wipe free space does. But there's no reason for me to be missing space weeks after running it. I haven't actually tried what Winapp2 suggested. Mostly because there are at least two folders that fit that description in my C drive and I'm not comfortable indiscriminately deleting folders which I have no knowledge of their particular importance or function. Also the folders combined hardly make up a GB worth of space.