You should also probably uninstall the Dell software from the VM. Your Windows installation, when in a VM, does not know about the physical world, only the 'virtual' one that we present to it.
As such, in the case of a display, installing drivers is not going to be helpful because Windows doesn't know it's talking to a Dell display by design.
VMware Tools will make sure all the proper drivers are installed, and it's simple to do as the other post here suggests.