First of all, last OS for your XPS was Vista, so I will provide Vista 64 bit drivers.
Network
Dell Wireless,
http://ftp.dell.com/FOLDER96569M/2/Dell_multi-device_A17_R174292.exe
Broadcom 57XX Gigabit Integrated Controller,
http://ftp.dell.com/network/R151326.exe
Those above you must have, next, Multimedia and USB device, those 2 could be unknown devices. Question. Did you upgraded your XPS by adding any PCI cards after purchase? If yes, do you know their models, and do you still have installation discs? If no, let proceed to the next section.
How to Find Unknown Device Drivers.
Every device connected to your computer uses a driver to connect and communicate with the computer. When a device's driver is not properly installed, the Windows operating system (OS) lists the attached hardware as an unknown device. This means the device is not recognized and cannot communicate properly with the Windows OS. To solve the problem, you need to identify the unknown device and find the proper device drivers. This task is simple and can be completed manually. Windows Update can also automatically locate unknown device drivers in some cases.
I
nstructions
Manually Locate Unknown Device Drivers
1. Open the “Start” menu and click “Run” to launch the “Run” dialog box. Select “Run” from the “Accessories” folder if you are running Windows Vista or Windows 7.
2. Type “devmgmt.msc” into the Run dialog box and click “OK” to launch the Windows Device Manager. The device manager provides a listing of devices connected to your computer.
3. Right-click the “Unknown Device” and select “Properties” to view the properties of the unknown device. Open the “Details” tab in the properties window.
4. Select the “Device Instance ID” from the drop-down menu in the “Details” tab. Locate the four-character codes after the “VEN” and “DEV” portions of the device's instance path. Copy both identification numbers and close the properties window.
5. Open your Internet browser and go to the
PCI database . Use the site search function to identify the unknown device's manufacturer by typing the four-digit code that followed "VEN" from Step 4 into the "Vendor Search" box. In some cases, the PCI database will provide links to the manufacturer's website. Typing the four-digit number that followed "DEV" from Step 4 into the "Device Search" box will bring up a list of possible device names.
6. Locate and download the device drivers from the manufacturer's website. Most device manufacturers provide updated drivers for free from the device's website. Install the correct drivers to correct the “Unknown Device” problem.
Use Windows Update to Locate Unknown Device Drivers
7. Click the Windows “Start” menu and select “Windows Update” from the menu. Click “Check For Updates” to allow Windows Update to connect to the Internet and search for updated software for your computer.
8. Click “View Available Updates” to review the updates located for your computer. These will include updates for your OS and drivers for hardware attached to your computer. Locate driver updates for devices on your system.
9. Click the updates for devices on your system and choose to install the selected updates. In most cases, this will resolve your problem with an “Unknown Device.”
You can actually run those 2 methods prior to installation of those 2 drivers I mentioned, since Broadcom might have Win7 drivers.
Report back.
P.S. Remember, try to keep at least PS2 keyboard, since this is native connection and it doesn't require any USB drivers, only generic Windows driver.
So far so good.