iPhone 3Gs. Purplera1n Jailbreak Removal. Help!?

So, I installed the purplera1n jailbreak on my iPhone 3Gs recently and now after downloading many things and sources Cydia is no crashing on me. I try to open it and it immediately closes. I don't know what else to do except remove the jailbreak. I have the Cydia program downloaded so that I can remove Cydia programs just like iTunes Apps but because Cydia keeps crashing that program won't let me uninstall anything. I also tried restoring and backing up my iPhone which did nothing. Is there a way to remove the Jailbreak or fix the crashing problem or anything. Please help me! Thank you