i am having some troubles and was hoping someone here could help me.

i use a pqi 2gb cf card in my canon powershot a80 and i have some videos that i tried to:
1)use a card reader to copy the files
2)used a usb to my camera to transfer files

both of these dont work. whenever i try to open the .avi files in windows media player i get an error. the videos play on my camera but wont play on my computer. on my computer they also take up space so there is info there, it just wont play. :mad2: this was never a problem with my 256 sandisk card.
can anyone help me?