Missing Drivers

Help pls!

I bought Inspiron 13 7000 Series 2-in-1 (7348) with a package of Windows 8.1.  However, I dowgraded the OS to Windows 7 Pro due to system requirement. After completely installing the windows 7 Pro, I noticed that there are four drivers missing in my device manager. I've tried checking with the Dell download center, but to no avail. These are the drivers that need to be installed:

1. PCI Data Acquisition and Signal Processing Controller
2. PCI Data Acquisition and Signal Processing Controller
3. SM Bus Controller
4. Universal Serial Bus (USB) Controller

Appreciate your help in finding these drivers.  Thanks.