Should I buy a new graphics card or a new computer?

[Chris Jones]

> Yes, but the Hardware Drivers tool (System->Administration->Hardware 
> Drivers) tells me "No proprietary drivers in use on this system" :-(

That is likely the problem ... It sounds like your system doesn't think 
it has an nvidia card (or does have the software sources set up that 
include them).

What software sources do you have set up ( either look directly in 
/etc/apt or if you prefer GUIs, "Software Sources" I think) ? Perhaps 
something went wrong during the upgrade....

cheers Chris