Problem with ATI Mobility Radeon 9000 on a Multivision laptop

[eezeepc]

This laptop crashes after about 15 minutes and looking at the error log, it seems it could be a problem with the Radeon video adaptor. Uninstalling it and using the generic VGA driver, it works fine, but of course I have lost some of the features of the 9000. I've downloaded the latest driver from ATI, but this fails to install - cannot find inf file. Should I also look for an updated chipset - its a N251C1 motherboard with a VIA VT8366/A chip? Any help much appreciated as getting quite fed up that I can't solve this problem.