No. Doing something like that is not a complete backup.
Just copying the Master Boot Record (MBR) is pointless (assuming you even could). Please read more about it and maybe you will see why:
Now, as far as archiving your running Windows system goes with 7z, again it probably won't work. Microsoft's DRM technologies alone will probably prevent you from restoring. There's also the problem of open (running) programs that will almost certainly cause problems with 7z. Then again, maybe you could archive a complete Windows installation if you did it from another computer - just not that computer. And even if you did I'm sure there will still be something that didn't get included such as hidden and/or system files. So hopefully, you know how to deal with file attributes. I also hope I don't have to go into file/folder ownership properties since that's yet another problem.
So to do a complete backup like what it seems you want to do you'd have to "image" the hard drive or at least image the one active partition that has your Windows OS on it. You'd also pretty much have to perform any imaging like that from another system too (ie. use dd from a Linux live CD, or possibly something that may have come on a bootable CD with your hard drive, or possibly something else from OnTrack perhaps).
Please don't get confused when it comes to Microsoft's "backup" utility too! I believe Microsoft lets you do something called a backup but it's not a "complete" backup since all you're really saving is your data and possibly any activation info. Therefore, in a complete restoration scenario you still have to reinstall (or restore) Windows. And then you will probably want to restore all your data which is the whole point of backing up.
So again, if you want to make a "real" backup of your entire Windows OS with all your data and everything so that you can restore it quickly in the event of a complete hard drive failure, you probably should be looking into "imaging" your hard drive or at least imaging the Windows partition. You might also like to look into RAID too but that's a whole other sack of worms.