How do I save and restore my window size and position?

Here is code I use to restore a saved window position, which includes checks to make sure the user hasn't saved a window position at one screen resolution and then restored it at a different screen resolution (which might cause the window's frame controls to be completely off the display -- we've all seen that, right???):

 BOOL SetWindowPosition (const HAB hab, const HWND hwndFrame,
                         const SWP swpConfig)
 {
     SWP swp ;
     APIRET ulRC ;

     // Initialize the window positioning flags.
     swp.fl = SWP_ACTIVATE | SWP_MOVE | SWP_SIZE | SWP_SHOW ;

     /* Check for saved user preferences for screen width/height in
      * config file.  Did user want to start maximized?
      */
     if (swpConfig.fl & SWP_MAXIMIZE)
     {
         // Get maximized frame window position and size.
         ulRC = WinGetMaxPosition (hwndFrame, &swp) ;
         if (!ulRC)
         {
             // Report error, and then ...
             return TRUE ;
         }
         swp.fl |= SWP_MAXIMIZE ;
     }

     // Did user want to start minimized?
     else if (swpConfig.fl & SWP_MINIMIZE)
     {
         // Get minimized frame window position and size.
         ulRC = WinGetMinPosition (hwndFrame, &swp, (PPOINTL) NULL) ;
         if (!ulRC)
         {
             // Report error, and then ...
             return TRUE ;
         }
         swp.fl |= SWP_MINIMIZE ;
     }

     // Did user have a saved starting position and size?
     else if (swpConfig.cy || swpConfig.cx || swpConfig.x || swpConfig.y)
     {
         LONG cxClientMax ;
         LONG cyClientMax ;
         LONG cyTitleBar ;
         LONG cxSizeBorder ;
         LONG cySizeBorder ;

         // Get maximum client window size.
         cxClientMax = WinQuerySysValue (HWND_DESKTOP, SV_CXFULLSCREEN) ;
         cyClientMax = WinQuerySysValue (HWND_DESKTOP, SV_CYFULLSCREEN) ;
         cyTitleBar = WinQuerySysValue (HWND_DESKTOP, SV_CYTITLEBAR) ;
         cxSizeBorder = WinQuerySysValue (HWND_DESKTOP, SV_CXSIZEBORDER) ;
         cySizeBorder = WinQuerySysValue (HWND_DESKTOP, SV_CYSIZEBORDER) ;

         // Maximum client window size excludes title bar.
         cyClientMax += cyTitleBar ;

         // Make sure x origin is within display boundaries.
         swp.x = swpConfig.x ;
         if (swp.x < -cxSizeBorder)
             swp.x = 0 ;

         // Make sure window isn't too wide, or negative value.
         swp.cx = swpConfig.cx ;
         if (swp.cx >= cxClientMax || swp.cx < 0)
         {
             swp.cx = cxClientMax ;
             swp.x = 0 ;
         }

          if ((swp.x + swp.cx) > (cxClientMax + cxSizeBorder))
             swp.x = cxClientMax + cxSizeBorder - swp.cx ;

         // Make sure y origin is within display boundaries.
         swp.y = swpConfig.y ;
         if (swp.y < -cySizeBorder)
             swp.y = 0 ;

         // Make sure window isn't too high, or negative value.
         swp.cy = swpConfig.cy ;
         if (swp.cy > cyClientMax || swp.cy < 0)
         {
             swp.cy = cyClientMax ;
             swp.y = 0 ;
         }

         if ((swp.y + swp.cy) > (cyClientMax + cySizeBorder))
             swp.y = cyClientMax + cySizeBorder - swp.cy ;
     }

     // No saved position -- move window to FCF_SHELLPOSITION location.
     else
     {
         // Get default window size and position.
         ulRC = WinQueryTaskSizePos (hab, 0, &swp) ;
         if (ulRC)
         {
             // Report error, and then ...
             return TRUE ;
         }
         swp.fl = SWP_ACTIVATE | SWP_MOVE | SWP_SIZE | SWP_SHOW ;
     }

     // Position and size this frame window.
     ulRC = WinSetWindowPos (hwndFrame, HWND_TOP,
       swp.x, swp.y, swp.cx, swp.cy, swp.fl) ;
     if (!ulRC)
     {
         // Report error, and then ...
         return TRUE ;
     }

     return FALSE ;
 }

Credit: Wayne Kovsky