What do you mean with turn off System Restore. Is this an avast option?
No, Right click the 'My computer' icon and choose Properties.
Go to 'System Recovery'.
Disable it and click aply.
Enable again if you want.
This will empty that folder.
Is this a problem
Yes, due to a USB keyboard limitation, the drivers for it correct working won't be loaded at that time and so, you don't have a keyboard at that time...
Can you change it to a PS2 or Serial one? After you can change back to the USB keyboard