blank/black screen after upgrade to fedora 20

[alain.roger]

Hi,

i have VB 4.3.6.r91406 working on Windows 7 x64 OS.
i imported from VMWare the fedora 19 as its webserver... after import into VB everything works great.

now i decided to upgrade fedora 19 to fedora 20 and everything is ok... grub2 is loading...fedora logo is filling in from empty to white and finally to fully coloured version... and next...blank/black screen.

when i boot in init 3 with nomodeset everything is ok, i get the text console and i can log-in as root.
when i run the startx i'm back to my problem with a blank/black screen.

So it seems problem is located in X,. after checking the xorg.0.log i found the vboxvideo module is not loaded....
how is it possible ?

how can i fix it ?

thx.

[Perryg]

While in init 3 install the guest additions so it will install the proper drivers for the new xorg.

[alain.roger]

Done, but while my virtualbox screen resolution is changing (for a larger resolution), everything still stay black/blank (screen)