Partitions formatted under Linux ext2,3,reiser,or xfs are not visible under windows-as regular disk partitions like D,E,F,etc. However you can still check their presence by using Partition magic( and sometimes the DRDos fdisk).
Also if you boot with the knoppix cd it should show your partitons with no problems. Then there is Qt parted.
If you want the data on your old partition I think that is gone.

You did not mention if your HD install was successful?