I have a Dell Dimension 8700 desktop running Windows 7. It came with 1TB of storage meaning 906GB of storage available out of the box almost four years ago.
Today my “C” drive has 434GB used.
My four libraries (documents, music, pictures, and video) take up 286GB.
That leaves 148GB of used storage unaccounted for. How do I find out what taking up all that space?
It’s freeware. Breaks down your disk space by item, graphs them, then creates a visual representation of your drive using colored blocks.
Have you used ‘disc cleanup’ to get rid of all your temp files?
Thanks, DC.
Try also CCleaner, the draw being that it gets constant updates to be able to clean up application programs, like browsers.
Glary Utilities is also good to have in your toolbox.
obPedant: that’s not memory. That’s mass storage. (Although this is probably going to degenerate into “everyone calls it that”. To which I argue, everyone can be wrong if that’s the case.)
An old Windows 7 installation will eventually chew up a fair bit of mass storage (in the 10s of gigabytes) in old updates and an eternal shadow archive of system files called “winsxs”. But that’s probably not the major contributor to your problem, which appears to be measured in hundreds of gigabytes, not tens.
Yeah, I use CCleaner about twice a month.
I just discovered WinDirStat and love it. Especially for the colorful depiction of my hard drive’s contents.
It’s a cool little program. Can be a bit slow if you have a big drive, but it does exactly what it says it will. It’s never shown me anything I didn’t already know, but it’s been extremely useful to confirm what I thought I already knew.
I was having disk space issues, and WinDirStat didn’t provide quite enough information to tell exactly what was taking up all the space.
It turned out it was this bug: Windows 7 log file compression bug can fill up your hard drive | Computerworld
I love WinDirStat, it’s a very attractive and useful display. Worst part of the program is my difficulty remembering the name when I need it.
In my case it’s mostly pop songs from the seventies.
Oh wait … this is a computer question.
Windows Directory Statistics is an application to show you statistics about your directories of files on your Windows computer. Like which directories are the biiiig ones.
If you repeat this mantra a few times a day for a week it’ll probably sink in. 
You can also create a shortcut to that app and name the shortcut “The colorful app to find really really big space-wasting files”
You’re right, gnoitall. I should have called it storage in the title.
I like WinDirStat but I’m not sure it’s telling me anything I hadn’t already figured out.
I think I’m going to move my downloads and libraries and an external hard drive and then see what the situation looks like.