Microsoft has released beta version of Windows 8 for developers to test and discover the features.
you can download the beta version from this link : windows 8 developer preview
This site is having two type of ISO, one is for developers with including developer kit and another version is without developer kit. You can download either 32bit or 64bit version as per your PC hardware. It is suggested that you install 64bit of windows 8 if you already having 64bit version of Windows 7/VISTA/XP so that you can dual boot your PC from boot loader(MBR).
You should also required a free partition to install windows 8 over it. If you are not having any partition you can make a new one by using windows disk management utility to shrink your existing windows partition(c: drive).
Now burn the downloaded ISO over a writable media(DVD) and boot from DVD , if your computer is not set to default booting drive as cd , you can change it by your BIOS settings.
After booting from DVD choose to install as custom and choose the destination drive that you create to install windows 8. when installation finished you will found dual boot mode with windows 8 with earlier version of windows(7/VISTA/XP).
Now enjoy windows 8 for free for one year from the date of installation. But remember that this is a beta version not a stable and final so use this only for testing purpose.
If you are not happy and want to uninstall windows 8 completely then follow the tips given below to avoid any problem and without loosing your existing windows data or settings:
1. boot from windows 7 or earlier version that you have in your PC
2. Now download and install easybcd from here, this is a very small and powerful software to edit your MBR(a file that is having details of bootloader).
3. In your easybcd goto add new entry and add windows 8 also go to bcd deployment and click on write mbr, now in mbr windows 8 has been added to your boot menu.
4. Now you can boot either from windows 8 boot menu to windows 7 or earlier or you can boot from windows 7 or earlier to windows 8 vice versa.
5. when you want to uninstall windows 8 , simply boot with windows 7 or earlier version you have and go to easybcd and click on edit boot menu tab now select windows 7 as default and delete windows 8 entry then save . once check by rebooting if everything fine then using disk management utility or by simply right click on windows 8 partition and format this partition. now your PC is as like as it before.
6. If using easybcd you are not not able to delete your windows 8 entry then try msconfig type in run command msconfing and enter , then go to boot tab and delete windows 8 entry.
7. Now reboot and and check the boot-loader, If your PC failed to reboot from HDD after above changes you can also use your windows installation dvd to repair your start-up problem.
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