If you have a ntfs/FAT32 use:
Runtime Software: GetDataBack
Data Recovery Software Products


If you reinstalled the OS on the same disk/partition something can be overwritten.
There could be 2 cases:
- The disk is very wide (ie 250GB) and you reinstalled the os only (few GB). Data could be still on the disk
- The disk is small and you installed OS and many other things. To do it you used a high %...