on displaying two images second image overlapps first image

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VC6

VC7.0

C++

C++/CLI

C

I'm writing a program to display multiple images on character select:
my code is on WM_CHAR:

case WM_CHAR:
		{
		
		switch((char)wParam)
		{
				
		case 'A': case 'a':
			
		hbmp =  LoadBitmap(hInst, MAKEINTRESOURCE(IDB_BITMAP2));

		break;
		case 'B': case 'b':	
	
			hbmp =  LoadBitmap(hInst, MAKEINTRESOURCE(IDB_BITMAP3));
			
			break;
			case 'C': case 'c':
			hbmp =  LoadBitmap(hInst, MAKEINTRESOURCE(IDB_BITMAP4));
			
			break;
		 default:
            break;
		
		}
		}
		break;

and on paint event:

case WM_PAINT:

		{
 hDC = GetDC(picBoxDisp);
  
 	    /* Create a memory device compatible with the above DC variable*/
	    MemDCExercising = CreateCompatibleDC(hDC);
             /* Select the new bitmap*/
             SelectObject(MemDCExercising, hbmp);
	    /* Copy the bits from the memory DC into the current dc*/
	    BitBlt(hDC, 0, 0, 200, 200, MemDCExercising, 0, 0, SRCCOPY);
DeleteObject(hbmp);			
    DeleteDC(MemDCExercising);
	
	SendMessage(picBoxDisp,BM_SETIMAGE,IMAGE_BITMAP,(LPARAM)hbmp);

Images are being shown but second image is over first and third is over second.
How to erase the previous image?