I'm not sure why the boot is so slow? How long does it take to get to the Windows 7 desktop when the PC is powered off?
I'm also not sure if this machine has a mSATA SSD cache drive which you might not have enabled. Likely it does as there is an Intel Rapid Storage Technology Driver. Try following the settings in this document here: http://en.community.dell.com/dell-blogs/direct2dell/b/direct2dell/archive/2012/04/13/dell-whitepaper...
My systems are too different to yours and on a dual boot to compare. Confer with 7headsdragon in this thread here:
They have used the same drivers on a similar system.
Try installing the driver via device manager without any additional ATI software.
I have purchased Dell Inspiron 15r 5537 from abroad. I was come by pre installed windows 8. Than I re-installed windows 8 pro 64-bit. its successfully installed but I cant install wifi driver now. the dirvers I downloaded from dell .
now what should i do?