Crashed Hard drive?

I was using Windows XP that didn't have a CD drive. This day i connected a CD drive and did my works. But suddenly when i removed the CD drive and restarted the computer, the windows didn't work. I went to the BIOS mode and checked the drive configuration. The hard disk was there but to my surprise it showed only 32.2 GB hard disk. The disk actually is of 120 GB.

I then connected this disk to another one as a slave drive but it showed that this drive is corrupted and is needed to be formatted to reuse. So i formatted the drive. Still the drive is shown to be 32.2 GB. What is the cause of this and how can i manage the drive?