Thank y'all for your time and help. I have just fixed the problem. For some reason my main SD-Card with all the games could not be detected on boot. So i copied every file exept the 3ds Folder onto my second 4gb card and it sucessfully booted. So i ran Gm9 and installed the boot.firm. Now i am able to use my ds with my main SD-Card again. Thank you all very much.