Crossed wires somewhere as it has not been suggested that you install any drivers only that you back up the ones that you need in case of an emergency, you can use a thumb drive for this.
The only driver that I see on the list that would not be needed for a fresh install is giveio.sys which is associated with Speedfan.
Regarding Microsoft .NET Framework 3.5 Service Pack 1, try saving it to a folder on your desktop, restarting in Safe Mode only (no networking) and then see if it will install.
Did you try this.
BTW, you can create a Dell account and add all of the drivers that you need to a list there, see My download lists info here
Bit busy today but will try and check back later.