There is no button....
Your realistic choices are...
Rebuild the Op System - for which you will need the media that you do not have
Investigate the problem you have that you do not disclose - and fix it.
Pick a restore point at a recent time in the past when the machine was operating correctly - and restore to that point.
Post another question stating the Op Sys you have and the specific problem you're seeing - you never know...
Good luck...
Peccavi, June 2010
