Windows 7 - Unable to install any USB devices

Here's the solution for the ones who might have this problem:
This worked for me in Windows 7 Ultimate 64bit!
You must have all administrator privileges!

1- Open Windows Explorer

2- Go to C:/Windows/System32/DriverStore


You will have a couple of folders and files.
You will have *.dat files and other file named: infcache.1

3- Right click every file (dont touch the folders!) and choose properties.

4- go to security tab

5- click Edit

6- choose your account and check the box: full control (see ss)

7- Click ok.

8- Repeat to every file

9- Select all the files (*.dat and infcache.1)

10- Press shift+del

11- Press OK.

12- Now, go to C:Windows/System32/Driver Store/File Repository/

13- Search for folder named usbstor.inf

14- Open it (if you have more than one, choose the most recent)

15- Copy "usbstor.inf" and "usbstor.PNF"

16- Paste those two files to C:/Windows/inf

17- Reboot your pc and voilla! :b