I deleted a condition by mistake, how can I revert my form back to the previous version?

I deleted a condition by accident. I have no clue what it was. It was already in the drive application form. Now it states the other condition forms will not work. How do I fix this.

The easiest thing to do would be to revert your form to the previous version using the revision history:

https://www.jotform.com/help/294-How-to-View-Form-Revision-History

This way you can go back to the working version to start again from there.