Hi there RoddyPoddy.
Did you use driver cleaner to remove all the Nvidia graphic related files on your PC prior to installing the 4890?. I'm only asking due to the fact that I've done this every time I switch between Nvidia and ATI with no problem at all.
This is the usual method below that I do. The reason I'm listing it is to see if you have done this and also for guidance to others who are maybe switching for the first time on their current system.
Uninstall the Nvidia/ATI drivers then reboot. Boot into safe mode (press F8 when booting). Run Driver Cleaner and remove ATI/NVIDIA drivers then shut down PC. Now change the cards over. Boot the PC, install and restart and that should be it.
You could also try a simple reset of the graphics card in the PCI-E slot first to see if that is the case. Also a CMOS reset if the re-seat fails. I hope you get to use your new card soon.
I used Revo uninstaller,ati cat remover,and "nasty file remover",when i boot with the ATI card installed,i can see the fan spinning,as windows tries to load,the fan gives an allmighty whoosh,as though its running at top whack,and this will continue until i hold in the power button to turn off my pc.Had the card in and out half a dozen times now,uninstalling/trying to install various driver revisions,and all i get is new hardware found,and my pc trying to install a driver for my new VGA device,and thats only booting into LGKC,or SM,it seems i,m on an endless loop however i try.
Is Driver cleaner free?,and thanks for the response,though i may leave things for tonight,it does look sadly as though i may have to reject this card
Just remembered,when i right click on my desktop,i can see the ccc tab,but if i click on it(or any ccc tabs in programme,s) it starts to do something,then nothing happens,as if the actual drivers don,t install,and also get error messages relating to no ATI software,or something along those lines,installed on my pc.
Man i have a headache.