Hi:
The only suggestion I can offer for the graphics is to try manually installing the W7 graphics driver as follows...
Download and run this driver file...close out of any error windows.
Go to the device manager and click on the Microsoft Basic Display adapter needing the driver. Click on the driver tab.
Click on Update driver. Select the browse my computer for driver software option and browse to the driver folder that was created when you ran the file.
That folder will be located in C:\SWSetup\sp58733. Make sure the Include Subfolders box is checked and see if the driver installs that way.
If that doesn't work, go back and choose the Let me pick from a list of device drivers on my computer and drill down to the specific graphics adapter shown on the list and see if the driver installs that way.
Another alternative would be to puchase some AMD Radeon HD 6450 graphics cards for your PC's.
Low profile with low profile brackets if you have the SFF desktop. Those cards will work fine in the 6005 and have driver support for W8.1/W10.
I can't answer your question regarding upgrading the processor.