my minecraft keeps crashing and i have tried re installing minecraft 1.6 and i dont know how to reinstall the regular minecraft because it seems to olny work if i have my other minecraft (1.5.1) on my PC i also dont have any mods

Put the summary of the bug you're having here

What I expected to happen was...:
to play minecraft

What actually happened was...:
keeps crashing

Steps to Reproduce:
1. go online to a server
2. wait about 5 min.
3.