If you receive this message while trying to update to Windows 10, it is because there are no drivers for your hardware and it will not be supported in Windows 10
"The display manufacturer hasn't made your display compatible with windows 10. Check with the manufacturer for support"
Windows 10 being a brand new Operating system has new minumum hardware requirements in order to support all the features and specifications of the new OS, so some older generation graphics cards are not able to be supported with Windows 10.
If you still choose to install Windows 10, graphics performance and display issues may occur due to using default Windows drivers that do not allow for full performance from the unsupported graphics card.