We never know what is the highest paid keywords. All we can do is to find the less competitive keywords and use those one to for your site by using Google adwords.
There are lot of keywords that are related to computer and technolgy. Computers, laptops, hardware, software and many mores. All are effective and high paying software
just try to google it ... my personal exp dont try to work on high paying keywords just focus on your niche because on high paying keywords there is lots of competition....