Dual booting with Windows 7

[Mohammad BadieZadegan]

Hi everybody.
I installed DF-BSD 4.2.0 on my last partition HDD that its first OS was
Windows 7.
After installing DF-BSD when I rebooted I get 3 choice F1 F2 F3,
F1,F2 DOS
F3 Df-BSD
Then only F3 is right and I could not boot to windows by clicking F1 or F2!
How can I enable and activate dual booting?