You basically just need to edit your grub boot menu.
As root, or using sudo, edit
The first thing to do is change the timeout value to something more to your liking.
Now you will want to enter an entry for your Windows hard drive. It should look something like this.
The tricky part is understanding how grub addresses the hard disks and partitions. The
(hd0,0) means the first disk and first partition. Look at your existing grub entry for your existing Linux installation. If it is something like
(hd0,2), you can be reasonably confident your Windows disk is going to be
In the grub menu,
default= refers to the menu entry that grub will default to on boot. The first entry will be
0, the second would be
1 and so on. If you wanted to change your default boot choice, you could either change
default= to the entry you want (such as
default=0), or make that entry the first in the menu.