Instructions
Click "Start" on your taskbar and type ̶0;regedit̶1; into the Search box at the bottom of the menu. Select the Registry Editor.
Click the plus sign by ̶0;HKEY_CURRENT_USER,̶1; select the plus sign by ̶0;Software̶1; and choose the plus sign by ̶0;Nimonix.̶1;
Double-click on the ̶0;RumbleFighter̶1; folder. Right-click in the blank space that appears on the right, click ̶0;New̶1; and select ̶0;DWORD Value.̶1; Name the new DWORD value ̶0;WindowedSecret̶1; and press ̶0;Enter.̶1;
Right-click on ̶0;WindowedSecret̶1; and change the Value Data setting from ̶0;1̶1; to ̶0;0.̶1; The next time ̶0;Rumble Fighter̶1; is booted it will be possible to run it in windowed mode.