New M6800 Win 7 Pro - Can't Install Wacom Drivers (or any others)

I assume this is a Windows issue. But I'm going to post it here as it may also be a Dell issue.

I have a new M6800 (about 1 week old). It is the base model from the website with Windows 7 Pro (64), AMD Firepro, etc.

Since starting it up for the first time there have been many Windows updates.

I cannot install any drivers.

I got a new Wacom Intuos Pro to work with my new computer, and I have tried to install the software and drivers from the accompanying DVD, but it fails each time. I ahve also tried downloading them from the Wacom website but it fails to install each time too.

I am still unable to use my new Wacom Tablet.

Additionally, I have a wireless mouse which infrequently stops responding when the laptop restarts, with the accompanying 'cannot install drivers' alert in the system tray.

There are also a number of updates, both Windows updates and Dell system updates which fail to install each time.

Is this likely to be a Windows issue? Or a Dell issue?
Or could it be a permissions issue of some kind (I am using the Administrator account)?

Any help, much appreciated.