What can I do to stop my applications from crashing?

I have osX.3installed. I recently backed up all my photos on a external flash drive. Some of those photos were on my old computer where I had os9 classic. Now all my applications crash every time I try to open them. Do I have to have os9 install on my current computer? I don't know what to do next. When I try to reinstall osx it won't open.

Thanks,

I hope some one can help me!