Problems related to dell studio 15

Hello,
greetings ,
i have bought a dell studio laptop 1 month ago it has been working fine with windos vista home premium.
But when i upgraded it to windows 7 , at that instant i faced two problems 1 is the ati radeon catalyst in which
has just reduced my laptop to simple one in which i can't see the videos clearly.
And the 2nd is that there at the start up a massege appear that mc afee resources are not installed correctly please reinstall it.
i cant help myself in these problems so what can i do?
please help me out of these problems.
thanks,

rajesh.