This post walks you through the steps to trace the causes and requesting reinclusion into Live Search engine index, if you got caught in the effort to stamp out malicious SEO when you are sure you are innocent of any overt crimes?

First confirm, if you’re really in the penalty box? Go to Webmaster Center, if not, then add your site first, and the authenticate your site. Else, click Summary tool -> Site status section. Blocked: Yes? means you’re penalized. Next check both Crawl Issues tool (review Malware infected and Outbound Links tool – select Show only outbound links to malware option). If any malware detected, clean up immediately. If not, then read Live Search Webmaster Center Guidelines, clear all issues and request for reinclusion Live Search Support page. 

More info:Detailed Article