Vista doesn't show the partitions in 'Computer'

I have an Acer Aspire laptop 80 GB . It had two partitions shown in 'Computer' directory :C and D. One year ago I installed ubuntu in the D partition. Thus it showed only the :C partition when I was in vista. Recently I decided to uninstall ubuntu, so I went to Disk Management and deleted D partition. Then I restarted the computer, repaired it(because there was the problem with GRUB) and restarted it again. Now when I go to 'Computer' it doesn't show the D partition, although it shows it as free space in the disk management. When I try make that free space a new volume, I get the message that there is not enough available space on the disk(s) to complete the operation. Can anyone help me, please??? I don't know what to do!!!

Sounds like the "repair" incorporated your old D: partition into your C: partition.
Partionable space on your hard disc will be shown as "unallocated" space. "Free" space
is space inside a partion that hasn't been filled with data yet. You will probably have
to shrink your C: partition before creating a new partition.

Open a admin level cmd prompt and type in

diskpart (this enters diskpart)
list disk (this will list disks connected to your computer)
select disk # (your disk number, should be 0 in normal setups)
list partition (there should be two partitions, your C and former D drive)

Let me know what you see there

Note: As a rule of thumb if you venture into the linux world, you're beyond basic user. If you're beyond basic user, there's no reason to go into Disk Management as it's essentially a safe mode GUI for the real disk management features in windows.

http://support.microsoft.com/kb/300415

This will give you the rundown on Diskpart in case others are curious.