320 GB Drive missing its 100 GB D: Partition

Hi all.
I need some help please.
All was fine yesterday.
When I fired up my computer this morning I found that my 100 GB D: partition has vanished
I took a look and the D: drive is now unallocated



Please is there a way to restore my D: drive.
I use it as a back up and have lots of family pictures on it.
Please help!!

> Mainboard : Gigabyte EP43-UD3L
> Chipset : Intel P45/P43
> Processor : Intel Core 2 Duo E8400 @ 3000 MHz
> Physical Memory : 4096 MB (4 x 1024 DDR2-SDRAM )
> Video Card : NVIDIA GeForce GTX 260
> Hard Disk : ST3320620AS (320 GB)
> DVD-Rom Drive : Optiarc DVD RW AD-7200S ATA Device
> Operating System : Windows 7 Ultimate Professional 6.01.7600 (x64)
> DirectX : Version 11.00
> Windows Performance Index : 5.8 on 7.9

Try this.

Recuva - Undelete, Unerase, File and Disk Recovery - Free Download

Thanks
I'll give it a try theog.
There is a lot of files I need of that drive all my tunes I wrote with music creator... oh man feel sick.
There has to be a way to undo whatever has been done.

I hear ya Product FRED.

Running a boot scan and chain smoking.

Will check out after scandisk is done.
Thanks Product FRED

Did you try the partition recovery in Partition Wizard?

Click the Disk at the top of PW window.

select partition recovery, do a quick scan of the drive, tick ALL the partitions you wan t to keep, click Apply.

SIW2 that was the fix thank you so much.
I owe you a beer buddy.
Thanks to all that helped.

still what happened so I or others don't make the same mistake.
like I said it was fine last night then this morn,,, well it's fixed.
thanks again.