If i backup my os...

[MiRae]

So basically if I backup my os to an external hard drive and my main hard drive breaks I can buy a new hard drive and restore everything without having to buy Windows 7/8 again right?

 

[thx1138v2]

Maybe. It depends on whether or not you have a CD/DVD of the OS, whether or not the external drive can be made bootable, and how you make the backup. The easy way to test it is to unplug the power connector to your internal hard drive and try to boot the machine from either the external drive and/or the CD/DVD. If you don't have a CD/DVD you'll need to make sure the BIOS will recognize the drive as bootable and boot from it.

I use a freeware program named EASUS to do a disk copy from my bootable hard drive to another hard drive mounted in an EZ-Swap2 device that lets me turn the backup drive off. That way the backup drive is only running when I do the backup and doesn't sustain any wear and tear from usage while I am not backing up.

EASUS essentially "clones" the source drive to the destination drive by doing raw sector copies. I've had one crash since starting this method and all I had to do was replace the bad drive with my last backup drive and start the machine again. Of course, I lost the work I did between the last backup and the swap over but I backup regularly so I didn't lose much.

 

[gouwufir]

you must know how to bootable, your thought is cloning rather than a backup. In my opinion, I suggest you try aomei backupper, first, backup to an external hd, second, make a bootable CD/drive