If your Setup.exe doesn't work/open and there is no HEIGHT and WIDTH values at regedit in the following addresses:
32-bit Win OS: HKEY_LOCAL_MACHINE\SOFTWARE\Gravity Soft\Ragnarok
64-bit Win OS: HKEY_LOCAL_MACHINE\SOFTWARE\Wow6432Node\Gravity Soft\Ragnarok
Then just add it your self.
Right click > New > DWORD type > HEIGHT (32-bit) value > Select the Decimal option for Base, Enter values with double click, then click Okay.
Right click > New > DWORD type > WIDTH > Select the Decimal option for Base, Enter values with double click, then click Okay.
For some Windows 7 64-bit, DWORD (32-bit) Value is fine, after you put in HEIGHT or WIDTH for the name, right click it again to modify the value as instructed above.
image aid for 32-bit Win OS::
image aid for 64-bit Win OS::
You can use this method to modify the windows size just by changing the values stored in the WIDTH and HEIGHT registries.