Buggy XP os

How to recover a file if its present in C drive and it some how got full..There is no space left on c drive.
I tried to edit that file, while saving i got the message "There is no space left on c drive"
I lost the all the content in the same file,it creates an empty file with same name..
Finally i was about to try PCI Recovery Tool..

letsee what going to Happen...