Minecraft Mod Problem. Help :(?

Okay, so a few days ago i downloaded the mods "Single player commands" - "Mo'Creatures" and "More Creeps & Weirdo's" they worked perfectly fine and we're installed correctly, i had also deleted META-INF, But today all my mods seem to not be working and any mod i try to install doesn't work \: Can anyone tell me whats going on?