I'll try to summarize the events leading up to my problem as best I can.

I have two hard drives. I tried installing Windows Vista Business on the first one to use in a dual-boot configuration with Windows XP which was on the second hard drive. Well, the Vista installation worked fine, but when I went to boot into XP, I found Vista's boot loader hadn't recognized Windows XP. Clearly frustrated, I tried several different things until I finally decided to format the first hard drive. It was horrible I lost my entire data from the Hard drive. Vista made my data vanish. I hate it. I tried using repair tool and many recovery software, but it did not work. Please help me out.

I know Vista doesn’t install itself easily. Something must have happened, that’s for sure. What software you have used to recover your data? One of the data recovery software I know is Salvage Data recovery Software for windows. My friend used the software and got his data back. Few days back I tried to recover the data of my office system, which I lost accidentally while formatting and it worked well. Try with their software. I think their site name is salvage data.
All the best.