Problem after installing ubuntu?

Hi all,
Before I had windows7 os, and I had two partitions:
C: - Windows directory, Totalsize:60GB, FreeSpace: 20GB, FileSystem: NTFS
D: - For Archive purpose, Totalsize:190GB, FreeSpace: 90GB, FileSystem: NTFS.

I launched ubuntu liveCD and I could see and mount C or D partition. After that I installed ubuntu in C partition with format and not wubi.
Now I couldn't find D partition, when I open disk utility it seems that D partition goes to free space allocated, but I didn't do anything with D partition.
Question is: How to retrieve my data from D partition ???
Please help me, it's very very important !
Thanks