I recently removed a virus from my computer and did a system restore to several days prior to the virus infection. Thankfully everything was removed and everything is fine. Except for Firefox which now refuses to open. I've attempted to start it in safemode and it still crashed immediately upon opening. I'm unable to get it to open to check for add-on issues. I did recently install the chatzilla add-on, however the system restore I did restored things prior to the add-on installation.