19) Repeat Boolean step. Now add shell modifier to the new objects. You should get something like this.

20) Create chamfered cylinder like this.

21) In top view place vertex  like this.

22) With a little work and you should get something like this.

23) Now create the rest of the monitor and cables to complete the picture.

24) Create scene setup and four lights. Set multiplier of first 3 lights to 2.5, and fourth to 5. Uncheck invisible.

25) Gray plastic material

26) Black plastic material

27) Cable material

28) For “desktop”  material use any print screen from your computer with 15 black reflection. Play with textures what ever you like.

For render use this basic settings.