Problems with ATI Mach32 Video Adapter on MCA Computer KB137363 - This article was previously published under Q137363 SYMPTOMS When you use an ATI Graphics Ultra Pro (Mach32) video adapter in a Microchannel (MCA) computer, the Windows 95 icons, menu arrows, and minimize and maximize buttons may not appear in Windows 95. You may also experience screen redraw problems when you use an 800 x 600 x 256 color resolution with this video adapter. RESOLUTION To work around this problem, follow these steps: 1. Use any text editor (such as Notepad) to edit the System.ini file in the Windows folder. 2. Add the following line to the [Display] section of the file: MemMapRegs=0 After you add this line, save and then close the System.ini file. 3. Change the hardware jumper on the video adapter to enable VGA mode, and then disable the on-board VGA controller on the motherboard. For information about configuring the video adapter and motherboard, please refer to each product's documentation. MORE INFORMATION Adding the "MemMapRegs=0" line to the System.ini file disables the use of memory-mapped I/O for the adapter, which may be necessary for MCA computers.