Technology stuff

1234567
Across
  1. 4. Who is the current chairman for Microsoft?
  2. 5. In terms of computing, what does CPU stand for?
  3. 7. Firefox,safari,and explorer are types of what?
Down
  1. 1. protects the internal components of a computer
  2. 2. which company works on IOS software?
  3. 3. main printed circutboard.
  4. 6. 'OS' computer abbreviation usually means?