partitioning - Lost all the data after installing Ubuntu 12.10

I installed Ubuntu 12.10 on my Laptop. While installing two options were available:

1. Install Ubuntu alongside Windows 7




2. Replace windows 7

My Laptop had 3 drives. Windows 7 was installed on C: drive and there was data on other two drives. I chose option to Replace Windows 7.

But now in Ubuntu, there is only one drive. Its size is approximately equals the hard-disk size and it is almost free, so it seems like all the data is lost.

Could anyone please help me on this? Would it be possible to recover the lost data?