Hi ÉderL
Try resetting the permissions on the local drive.
Do this from the command line:
Open Start, type: CMD
Right click CMD
Click Run as administrator
Type in at the prompt OR Copy and Paste these one at a time : (Hit enter after each)
TAKEOWN /F C:\ /R /D Y
Once you have taken ownership, then you have to set the permissions; for this, you use ICACLS:
ICACLS "C:" /reset /T
Exit, restart then check if you can now execute the commands.