Are you sure you don't have an old driver cd left over, that came shipped with your hardware? If you lost track of what's under the hood, best way to check it out is to crack it open and have a look. There may be stickers or other things printed on the individual parts that may give you a clue. Computer manufacturers like Dell and Asus for instance have a pretty vast archives of what comes shipped with what, and give you schematics to further help you identify individual parts. Usually these archives contain driver packages as well.
The driver the computer manufacturer (not the GPU manufacturer) recommends is always a good one to default to when dealing with problems such as these. In fact, should you be able to find out more about your GPU, this also counts double for the GPU manufacturers. The chipset in the GPU may be NVidia, but it could have been put together by Zalman. In that case, go with their drivers before you try out a 'pure' NVidia Catalyst driver (or whatever they are called these days).
So long as you have a recommended, stable driver you can venture into other things. General rule with drivers: if it isn't broken, don't fix it.
[INDENT][SIZE="1"][font="Courier New"]'..[color="White"]t[/color]olerance w[color="White"]h[/color]en fog rolls in clouds unfold your selfless wings fe[color="White"]a[/color]thers [color="White"]t[/color]hat float from arabesque pillows I sold to be consumed by the [color="White"]s[/color]now white cold if only the plaster could hold withstand the flam[url="http://bit.ly/foT0XQ"]e[/url] then this fountain torch [color="White"]w[/color]ould know no shame and be outstripped only by the sun that burns with the glory and [color="White"]h[/color]onor of [color="White"]y[/color]our..'[/font][/size][/INDENT]