I have a Windows 7 system and two netcards. One is linked to the internet probider. The second one connected to the router. How can I set up all this to allow my computer to work as router, allowing router to get an IP-address from my computer and internet access?
The only way that I can think about doing this without conflict is to connect adapter 1 to adapter 2 and then have them both connected to the router, you can't physically turn your pc into a router.
A HUB can allow you to do this.
adding on from my own answer. Take a look at ICS (Internet Connection Sharing) a useful guide by Microsoft is here: http://windows.microsoft.com/en-US/windows-vista/Using-ICS-Internet-Connection-Sharing
Also take note from this support article, although it's for Windows XP it may still come to of some use.