What to do when your hard disk loses a partition

[Guest]

Hello,
My hard drive had two partitions of 141 Gb's then after installing a few updates I am down to just the C drive, the D partition of the drive has gone. When I try to do a reinstall for my back up disks it say that i can only reformat 141gb instead of 280, can any one help me recover the other partition.

 

[evongugg]

Run manufacturer hard disk diagnostics.
Try partition and data recovery software.