Nice! I got it now...
I figured that the size and location was being replaced by the values gathered from the GetWindowRect! So, since now that we are literally defining the coords and dimensions, then I could omit the GetWindowRect function right? :D
Here's my code now;
DlgProc proc uses ebx esi edi hWin:DWORD, uMsg:DWORD, wParam:DWORD, lParam:DWORD
...
.elseif uMsg==WM_COMMAND
.if wParam==IDC_BUTTON_MAIN_SET
invoke SetWindowPos, hWin, HWND_TOPMOST, 0, 0, 0, 0, SWP_NOSIZE or SWP_NOMOVE
...
Now all i have to do is figure out how to correctly set it using checkboxes... pft!
Thanks a lot chris! This helped me a lot!