I am using Ubuntu 12.04 and Windows 7 on my laptop, where I had installed Ubuntu alongside Windows. Now, I would like to, if I can, upgrade to Windows 8 without any formatting. How would that affect the booting process? Would it cause any problems with Ubuntu 12.04?
If you UPGRADE your windows, it will not be problem. What I experienced about windows 7 to 8 installation is this:
You can upgrade Windows 7 32-bit to Windows 8 32-bit only. -32-bit to 64-bit is not possible in upgrade process. -You have to buy a saperate DVD to go from 32-bit to 64-bit.
This UPGRADE should not modify MBR and you will be able to keep Ubuntu as it is.