As i have stupidly failed the war with the auto updater, i have resorted to playing single player. But i downloaded the /chat mod to give items for single player ONLY and it f'd up minecraft now it wont load up. Any help?

Delete .minecraft. And download a fresh. . Thts what id do. Sorta turn it off and on again lol

Steve you fail!

You can't launch MC or is it just the SP world?

Go to: "yourname" > Appdata > .minecraft and delete the bin folder, then launch minecraft and let it download a fresh one.. Fixed.

Not much help now, but for future good practice, whenever a new Minecraft update comes out, make a copy of your bin folder (I call mine "Vanilla Bin") so that you can easily revert if your Minecraft is messed up by a mod.

Also comes in handy if you accidentally update before the server is ready.

Oh so im not the only one who does that. yet mines called Sir Binnery the 2nd