My laptop was working fine. I did not install any new application. If automatic Windows updates happened then I am not aware because machine was on for few days. I shutdown my machine last night and tried to reboot this morning -- it gives following message: Dell MediaDirect Express cannot access your hard drive. This may be because you have enabled Microsoft Bitlocker (Drive Encryption). MediaDirect Express is not accessible when Microsoft Blocker is enabled. It gives me exit sign and when I click it -- it shutsdown the machine, Please guide me what to do -- I cannot boot my machine anymore.

Sorry, this is Vista forum you had posted to.Please repost to XP forums : http://social.answers.microsoft.com/Forums/en-US/category/windowsxpFor the benefits of others looking for answers, please mark the suggestion as Answered if it solves your problem.