I think what you have here is a significant issue.
The SMC Bus driver is the main chipset for the motherboard so,
no usb and others will not function correctly.
PCI device is likely a modem which isnt needed.
The USB is likely USB 3 from another outside vendor.
Now as for the chipset you didn't even mention if you installed 32 or 64 bit.
So it will have to be trial and error here
Here is the link for the 64 bit one i believe.
http://www2.ati.com/drivers/13-4_win...d_ccc_whql.exe
This is the 32 bit one I believe
http://www2.ati.com/drivers/13-4_win...d_ccc_whql.exe
Now the USB is gonna be tough
I would advise going and getting aida 64 and getting their program and try to identify
who made the usb 3 chip. It likely will tell you who made the USB 3.0 chip so we can get the drivers.
Now why did you downgrade to windows 7?
If it was only to get back the traditional start button and programs list and desktop.
You could have done that very very easily with any of several small free programs like Classic Shell.
http://www.classicshell.net/