Won't let be start game when I've uninstalled, then reinstalled

So some certain texturepacks wasn't working for me so I thought if I uninstalled, then reinstalled the game it might solve the issue. So I deleted my .minecraft folder and installed the app by going on the Control Panel. Then I went to the MC website and installed again and I pressed "Play" and then after the Mojang symbol came up, the game crashed. It was doing this over and over again. So I went to the recyle bin and restored the old .minecraft folder and the app and I've merged them. It still doesn't work and crashes. Any help would be kind. I have an Enderdragon fight planned with the SMP I play on this Saturday so I would really like it if it was fixed before then so I don't miss this out. I am also sorry if this was reported before.
Thanks
WesterMC