Seems like you forgot to install the motherboard drivers. Get them with your service tag from dell.com.
I have Dell studio 1558 and few days ago my computer displayed blue screen and failed to run. I replaced the HDD, which was apparently the cause and I installed a fresh copy of Windows 7.
The problem is that now, when I use the windows Restart button the computer does not restart but just shuts down. Moreover, when it is shut down it does not stop completely, but the cooling fan continues to run and I have to use the power button to stop it completely. Any ideas what is the cause and how to fix it?