Hadrive not accessible.

ITs the wierdest thing, I was runing windows Xp with 2 hardrives. The
secondary hardrive 300Gb is a Segate. It was almost full. I formated my C
drive and installed windows Vista, now When i go to my computer, I see C, and
D. my secondary drive shows up with a red line showing that its almost full.
It shows that there is 1.03 GB left and that it has 279GB of used Space. When
i go to it, its empty, I can put stuff on the 1.03 GB that that it has left,
but I can't see my files.
Winamp was able to access it and find the songs, and play them that are on
there, but I can't see it with Explorer. Its formated as a primary drive.
NTFS. What can I do?