I keep meeting my friends who have lost their windows activation one way or other. Now first of all let us look, how you can lose your activation.
1. File corruption : By far the biggest culprit. System files get corrupted due to virus or hard disk failure or by some shit software you downloaded from torrent sites. The windows gets corrupt and you have to reformat and re install.
2. Virus Attack : Hackers are out there to harass you. They may not get any valuable from you but anyway they get the kick out of troubling a large number of people.
3. You are trying something geeky: Lets say you are installing Fedora in dual boot with windows. If you are not careful, fedora will wipe out the windows boot files.
4. You system is slow and someone tells you that re installing the windows will make it faster.
5. Un installation of some software made it unstable. The antivirus software are notorious when you uninstall them. They don't like goodbyes.
So now what to do. Simply reinstall the Windows from your CD/DVD and go online. On most of the cases your windows will be activated immediately. On some other cases you might have to call their customer care and one machine or a person will talk to you and give you some numbers which you have to feed. That will activate your windows.
But some people are really shy. they dont want to talk to a machine or person to activate their windows. They think that after paying money to MS the OS is their property and they should be able to do whatever they want with that. True sir, But MS doesn't sell the exclusive rights to us. They only licence it for use on one computer. Otherwise an OS built by thousand of Software Engineers can't be yours for $200. Thats their viewpoint not mine. I am fully with you.
But the consumer cannot do much in this regard. Sure you can drop Windows and go mac way or linux way. But if you want to eat your cake and have it too then there are software to help you. I personaly have used many of them and found most of them very good. the best one is
ACRONIS TRUE IMAGE ; It never failed me.
NORTON GHOST; 90% time it served me good.
PARAGON BACK UP : 100 % good.
There are others but then their success rate is less than desirable. Mind it, its my personal experience. But I tell you, if you go with Acronis, you will never regret your decision. The best part is the older versions of Acronis like vs 8 or 10 are available free on many forums. They are as good as the latest system and as reliable.
You dont have to reinstall your system ever again. You whole C drive will be backed up by Acronis including all the softwares and updates and whatever you have on that drive. If anything goes wrong with your system then simply restore the image made by acronis. It will take 10 min for a 40 GB partiton. And you are as good as new.
