You should be able to change resolution in KDE, but that will not change the resolution during boot up, it only changes the resolution used after X windows starts. If you don't care about boot up, vga=normal should work. If you used vga=normal as a cheat code, it should stay that way after hard drive install also.

It is not a good idea to always log in as root. There are no safety warnings (like "are you sure?" in windows) and you can really screw things up by mistake when you run as root.