I need help with boot order on dual OS pc?

I have a PC running Windows 7 and Ubuntu. When booting I get that normal screen where you can choose which OS to load. By default Ubuntu is highlighted and since I am using Windows more, I would like to make Win7 default.

Apparently I can, or should, be able to change this in boot settings, but it doesn’t work. Also when I simply format the Ubuntu partition I can’t start computer at all, something with GRUB prevents it.

So I guess I have to questions:

1) How can I change boot order and make Win7 default?
2) How can I remove Ubuntu?