Howto: Dualboot and Win7x64 - EFI GDT Problem solution

Hia all

I have get my Laptop with WinXP, and want to test Win7 x64.

It was not easy to find a way, to install Win7 without formatting the disk, so i share my research.

I found many Threads in the internet to this topic, but funny, a mac Forum point me to the Solution.

The Windows7 Images seeems to be incompatible for some Bios with EFI support. On some Sony Vaio`s Laptops you could press ESC while booting, to emulate EFI Support. Other Brands you will find other ways to enable - all 32 Bit Users have finished here.

Most EFI emulated installations dont support x64

Here we go:

(only needed for x64, if you doesnt want to format your disk on some Bios and Mainboards, or with )

Create 3 folders c:\efi-iso c:\efi-exe c:\efi-dvd

Download oscdimg.exe from ( http://blog.aproductofsociety.org/files/oscdimg.exe) into c:\efi-exe

Extract the Win7 iso using 7Zip or WinRAR (Or copy the contents of the DVD) into c:\efi-dvd

Start up a command prompt (Start -> Run -> cmd)
Type: cd c:\efi-exe

Type: oscdimg -n -m -bc:\efi-dvd\boot\etfsboot.com c:\efi-dvd c:\efi-iso\Win7X64.iso"

Burn this ISO, and Boot from - this ISO force now the EFI Mode for x64

Hope this help some other people too. Unfortunately i doent have the Original-Thread and links anymore, it is not written by me - i found it on the net.