We have that same model of desktop computer (HP Z420) at work. Unfortunately, the vendor's web site isn't always the most accommodating source when it comes to device drivers.

If at all possible, try to find another HP Z420 that is up and running with Windows 7 x64. Copy the %SystemDrive%\Windows\System32\DriverStore folder to a DVD-R or an external USB drive. Once you have it, you can temporarily attach it to your computer and do the following:

1. Within Device Manager, right-click each missing device and select Update driver software...

2. On the next screen select Browse my computer for driver software

3. Navigate to the temporary location of that DriverStore folder, ensure that the box is checked to Include subfolders and click Next

Follow the same procedure for every problematic device, and each driver will be installed successfully.

We have that same model of desktop computer (HP Z420) at work. Unfortunately, the vendor's web site isn't always the most accommodating source when it comes to device drivers.

If at all possible, try to find another HP Z420 that is up and running with Windows 7 x64. Copy the %SystemDrive%\Windows\System32\DriverStore folder to a DVD-R or an external USB drive. Once you have it, you can temporarily attach it to your computer and do the following:

1. Within Device Manager, right-click each missing device and select Update driver software...

2. On the next screen select Browse my computer for driver software

3. Navigate to the temporary location of that DriverStore folder, ensure that the box is checked to Include subfolders and click Next

Follow the same procedure for every problematic device, and each driver will be installed successfully.