Win7 booting problem after lion #iATKOS

Hello guys I am having quite a big problem. I had my win 7 installed after that i changed my bios from IDE to AHCI and installed niresh lion. I had ni oroblems with installation only that I couldnt install my network and sound cards i have been searching for kexts for a long time and now i got tired of it. Now I just want to install my win 7 back I changed bioa back to Ide and put my win7 dvd into cd rom. The problem is thaz it eont boot now. It says that i have to reboot and select a proper boot device. I really dont know what to do.





Thanks for any advice





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