Retrieving applications installed on a separate hard drive?

I recently made a fresh install of windows 7 ultimate on the existing C:\ drive due to the system running incredibly slow and crashing constantly. i decided to install all of my application on a separate hard drive so that C:\ would be dedicated to the OS. Unfortunately a week after the fresh install and installing all of my applications to my G:\ drive my c:\ drive decided to die on me. i have now added a new HDD and reinstalled win 7 ultimate. my only problem is some applications refuse to run and none of them appear on my Start>Programs list. how can i rectify this. All help is much appreciated.