you would notice a line "default" in the grub.conf file
Code:
1]open konsole
2]get superuser by typing "su" and providing the password
3]cd /boot/grub
4]kwrite grub.conf
you would notice a line "default" in the grub.conf file
Now see after how many entries is your windows entry.
I mean check the title number (count, on which number you have your windows entry may be titled as "Others" (if you havent changed))
Example:
If you have got two more titles before your windows title then your windows should be the
Third Entry
so to boot windows by default make the default value to 2. Because the 1st entry is considered the Zero th entry.
so make it
"default=2"
and save.
Please respond if it helped and, if you did not understand anything, please say, and please let us see your grub.conf file