recover overwrite partition

hi, i have a question about how to recover stuff that i have on my hard drive before i install the operating system over it. What happen is that i have problem logging into window, so what i did is i put in the window xp cd trying to fix it. However, i coudln't get it to fix, so what i did is i install window xp (fresh) over the old partition that i have on my hard drive. I have a 160gb hard drive, but after installing window xp, i only have 110gb left. Under the program files, i can see some of the programs that i have installed before installing window xp (home edition) again, but when i click on it, it gives me an error message. I don't really care about all the other program, all i care is getting the stuff that i have on my computer. Are there any ways to get it stuff back b/c i know it's in there some where?
Thanks