Snippets bug – not deleting code snippets

Hello, I have a slight problem and wondered if anyone could help me. Been using snippetts for years and never had a problem till yesterday. I added a few lines of code which I don’t need. I can’t seem to deactivate them or delete them. They look like they have been deleted then come back. I have tried to uninstall the the plugin with the complete uninstall function ticked but it just comes up with link expired. I have a feeling the code that is running is causing problems. I don’t want to uninstall the plugin without getting rid of all its data so I can’t start fresh Any help?

I can’t add any screen shots to show you the problems.

Thank you