How do I restore a ''missing'' partition

Hello,

I had three partitions set-up. B, C, and D. The missing one is B, the other two are fine and working. Programs that were installed on the B partition, and files can somehow be found by using the search option, but I cannot access them because the location ''refers to be unavailable''.
I've tried to google the solution and I've already tried two things.

1. Managing storage units by right-clicking My computer, but that didn't help. It seems though the B partition, along with its contents and storage size are missing entirely.
2. I've tried the command chkdsk on cmd. It told me that the disk was already in use and if I want to check the disk after a reboot. Naturally, I typed ''Y'', rebooted the system, it checked the file, but nothing out of the ordinary appeared. When the system finished rebooting, the disk was still missing.

I didn't try to use other methods on google because I couldn't find this problem occurring to anyone, so here I am, asking for help.

The B partition stands for Backup, it was around 100Gb large, and I had around 60Gb of occupied space there. (Photos, shows, etc.)

What do I do?

A & B & C are reserved letters and M$ will not play nice if you try to use them. A & B were used for floppy drives originally and are still reserved. C is used for the system drive.
How you recover your files is for someone else that works in that area.
Art.

The terminology between Disk Label, Partition and Volume can be confusing. A Partition will create a new volume on a disk. Volumes are labelled volume 0, volume 1, volume 2, etc.

Do you mean the volume is now missing? If so this forum thread may be of use: Partition Volume Missing.

We need a screen shot from disk manager showing all the details

Do these help?

Disk manager shows only c and d and a blank 100meg so I dont see were 100gig has come from unless you have resized a paritioninto d