The evaluation copy of Windows 7 got expired

I had installed Windows Vista on my desktop which burned all my resources including hard disk , so I decided to install evolution copy of Windows 7 which was recently available in market.The updated copy I installed it on my desktop and entered product key into windows activation, it got accepted and everything was working properly . Now suddenly after 6 months I am being told that your Windows 7 copy has expired and my desk top screen turned to blue . All application we used to support the web design clients which are not available in the market I have installed them on to my computer , can any one suggest me how I can run my desktop again without reinstallation of perating system .

As you are not able to start your computer try to start in safe mode by perssing F8 when you start your computer untill you get Advanced boot Menu using arrow key select Safe Mode opton and hit Enter .When computer starts in safe made open control pannel and get to system at bottom of the page look for the activation and see that you can again activate it again by entering the product key . If its not working then try to communicate microsft as they only can fix cdkey and validation erros . Hope you are able to solve the problem , but still my personal view would be to reinstall new copy of windows and back up your applications .

Take the back up of all your documents and whatever else you want and store it in an external hard drive or to DVD. IF you still have the restore partition then you can reset your desktop back to its original operating system, if not then purchase the restore disk from your maker. The expiration period of any operating system is released by company.,as your evaluation copy has expired you cannot start your computer and thus you might need to purchase the real version of Windows 7 and do a clean install, this will put the the older version of Windows into C drive named as Windows.old which you can delete . The files and data that you stored on external hard drive store them back on the desktop retaining some of your previous settings .

There has been time since computer is unable to start, you have to clean install the fresh copy of Windows 7 as there is no support provided by Microsoft to revert back to old operating system windows vista . You have to format the drive in which the windows was installed and the best way is to disconnect the other drivers wile installation to remain on safe side. Your applications will be deleted so try to collect them again and next time remain alert that your windows do not get expired.