Vidoe option on camera used to work, but now:...

my camera us a sony cyber-shot dsc-40. I have a memory stick with 128 MB (2 actually, and it won't record on either one). I have been taking videos with this camera for 2 years now, and it worked fine. then about a week ago I was deleating old vidoes off of my memory stick and then the video function stopped working. I had no idea what was going on because my screen was constantly white, but I found this site and tapping the 'sweet spot" worked great. the screen says "640(Fine) is not available.
I tryed reformatting the memory stick, but that didn't do any good. Please help!!!