You have Mirage 3 onboard video adapterIt supports pixel shader 2.0 and hardware tnlcan anyone please tell you if vertex shaders are required in most of the games

If you are talking about any games released in the last 3 years (since 2004) you will definitely be disappointed with your graphics solution. You will probably find most of the games will not run at all and any that do will run very poorly - extremely low framerate and/or graphical fidelity. Most games now require at least pixel shader 3.0 and furthermore, games will gradually be moving over to direct X 10, which also requires modern hardware. If you are in any way serious about playing mainstream games on your PC, you need to look at getting a dedicated graphics board. Something from ATI or nVidia's mid-range would probably do the trick for around $100US or £50.