828gb Missing on my 3tb hdd

One question from another member: is SP1 installed, and are all your Updates up to date?

Was SP1 installed on your system before?

There is no good reason not to keep W7 up to date, there is always added functionality and they are not going to document every change in an update, just the majors.

I would suggest installing SP1. Note: SP1 is a major upgrade and should be installed with focus. And always alone (not with any other update).

• Perform a Disk Cleanup and a Defrag beforehand.
• Temporarily suspend any Antivirus software.
• Start the installation and then leave the PC alone. Push your chair back so you cannot reach the desk, go make lunch, anything. Don't multitask.
• When Windows restarts after the install, continue to leave the PC alone. Wait until the hard drive slows down and nearly stops writing. This can take up to 15 Minutes.

Check to see if you can see all of your drive afterward.

On a slightly different angle are there lots of windows backups on the drive, after a reinstall you may not have permissions for the folders so they would be there and intact but right click properties would show them as 0 bytes

Also, on disk recycle bin ?? have seen lost space to this before but not on this scale