Recently I bought an interactive horse-riding game called ‘Riding Star’ for my daughter. Installation proceeded smoothly but when trying to play the game the following error message appears: ‘Unable to switch to video mode 640 x 480′. Our computer is a Compaq Presario 524CDS, 486 DX4 100 MHz, 4.3gb hard drive and 24mb RAM running Windows 95b. The video adapter chip is Cirrus Logic CL-GD-5424 that has its own driver. Attempts to run the game using a different driver (e.g, Generic VGA) have not been successful, neither has manually changing the screen resolution to 680 x 480. I have not been able to find any updated Windows 95 drivers for this model Cirrus Logic chip. I think I have diagnosed the problem correctly as being with the video adapter not switching to the desired screen resolution. If you have any ideas or fixes for the problem we would be very grateful.

Firstly make sure that you have the latest version of DirectX installed on your computer. You can download the latest version from www.microsoft.com/directx/. However, I think the underlying problem is that your video card does not support DirectDraw (judging by the age of your computer). I had a look at the System Requirements for Riding Star and it requires a 2mb SVGA video card supporting DirectDraw. DirectDraw is a software interface which allows video processing to be completed by the computer’s video card rather than CPU (as the CPU is frequently busy with other tasks). The software interface also allows games to have direct access to features of the display device.

To test if your video card supports DirectDraw, install DirectX (if not already installed - it should have installed with Riding Star), then go to the ‘Start’ menu > ‘Run’ and type ‘dxdiag’ (without the quotes) and press the ‘Ok’ button. This will open the DirectX Diagnostic Utility. Click the ‘Display’ tab and look under ‘DirectX Features’. If ‘DirectDraw Acceleration’ is disabled, press the ‘Enable’ button and click ‘Test DirectDraw’. If all is ok, try to run the game again. If you cannot enable DirectDraw, you will find that the ‘Enable’ button is greyed out and labelled ‘Not Available’, the ‘Test DirectDraw’ button is greyed out, or the DirectDraw test does not work. In this case, your video card is more than likely not DirectDraw compatible.

The good news is that you can probably pick up a DirectDraw compatible 4mb or 8mb video card for around $50 - $75. However, make sure that it does support DirectDraw. These cards should be available from a computer repair shop. Larger computer retailers normally only stock more expensive video accelerator cards (in the $300 - $500 range). I would spend no more than $75 on a video card for your purpose.