hello, this is shameful, but i need to solve this at once. i've been playing around with my network's active directory and opened the domain group policy and changed some settings there, i remember that i enabled an option titled "Run only allowed Windows applications", and from that point i wasn't able to do anything with my server, i can't even open a notepad, although i'm the domain administrator, i really don't want to reinstall the domain again, so please help me out, thanks for your time.

YOu are really in the wrong forum here, but get back into GPMC and undo that 'run only allowed windows apps" if you set that, but then don't list any apps, you can't run any apps. You may not be able to get back into MMC...if that's the case you'd probably need to use MMC of a non-domain member workstation and connect to ADUC/ADSIEDIT/GPMC to undo your changes. Try the server admin forum for more help.