you might be able to contact google/mcafee or whoever blacklisted/ labeled your site. they usually have a "request review" section for webmasters
no my forum is about electronics products. btw i forum use to get spammed on daily basis and i use to delete that daily.
It probably got spammed at one point by some virus-posting bots, hence causing it to get blacklisted by Google (or whoever manages the list) as a dangerous site. Try submitting to Google for reconsideration: Some helpful info here: http://sites.google.com/site/webmasterhelpforum/en/faq-malware-and-hacked-sites
