I have installed Win7 first, then installed Ubuntu and that made Ubuntu the 1st choice on the boot order, but since I am natively a Windows user I tried to put Windows on 1st place via grub customizer, but after I pulled it on the 1st place, when I choose windows 7 on boot meny it gives me an error "A disk read error occured. Press Ctrl+Alt+Del to restart".
I did exactly like in this tutorial: http://itsfoss.com/windows-default-o...ntu-1304-easy/
After I have changed the boot order in grub, there is "on /dev/sda1" next to the "Windows 7" text in the boot menu. Before I changed boot order I am 99% sure there was only "Windows 7", without "on /dev/sda1". My guess is that the disk names in windows and linux are different so Windows can't find the path grub has writen for it where to boot from. But I am a total noob for linux and I don't know how to fix this!