can I recover a windows file after installing ubuntu

How did you install it?

If you told Ubuntu to use your entire drive replacing windows then sorry its gone. If you have it backed up you should be OK but otherwise no

Origional op system was vista.had a problem reading the boot drive. I thought it was a hardware prob. I loaded ubuntu from CD. I was able to read the drive. I transferred the data I needed to an external HD. I then reinstalled ubuntu over vista. Don,t remember a choice of partioning.
I then attempted to transfer the data to my main desktop. Couldn't do it the drive went totally south. I think my only course is to try to find the data on the ubuntu installation.. I hope I am making some sense out of this problem.

From a terminal (CTRL+ALT+T) Enter the following and post the results back here

sudo fdisk -l; mount | grep ^'/dev'

This will tell us how the drives are set up on your computer and if your old drive still exists or not. If as I suspect then the whole file system has been replaced. I don't know if it's possible at all to recover the data but it certainly won't be easy.

This will depend on what Ubuntu does with the unused space when it formats the drive. If it overwrites it its gone if it just marks the fact that its free for later use then a data recovery expert may be able to recover it for you but it will be expensive. And this assumes that Ubuntu has not put new stuff where the data you want was.

If you still have the drive you used for the backup then that may be your best option. Even though the hardware has died the data should still be be stored on the platters and a expert may be able to recover it for you at a cost.

This is why you need good backups