Download one of the official iso from here Microsoft: http://www.microsoft.com/en-us/software-recovery
Download the Config removal tool from here: http://www.itso.dk/files/winapps/eicfg_removal_utility.zip
Run the eicfg_removal_utility and point to your iso file.
Download the Windows USB/DVD Download tool from Microsoft: http://wudt.codeplex.com/ or http://www.itso.dk/files/winapps/Windows7-USB-DVD-tool.exe
Run Windows7-USB-DVD-tool.exe and point to Windows 7 iso and either a DVD or USB key for destination.
Boot and install wanted windows 7 install, use your license key.
Now for danish language pack.
download: http://www.itso.dk/files/lp.cab
Copy file to c:\lp.cab
start CMD as administrator
Run the following commands:
dism /online /add-package /packagepath:C:\lp.cab
bcdedit /set {current} locale da-DK
bcdboot %WinDir% /l da-DK
reg delete HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Control\MUI\UILanguages\en-US
Sources:
http://code.kliu.org/misc/winisoutils/
http://superuser.com/questions/331779/how-can-i-change-the-language-of-windows-7-to-english#331780