I agree with Rob.
At first sight this is a desireable name, and popular judging by the other significant TLD's that are taken.
However, popularity does not always mean high value. The word "computer" is not ideal in a domain name, "pc" is much better and in most cases more appropriate. The best domains are short ones, and "computertraining" is rather a mouthful at 16 characters.
The meaning is perfectly clear, and the market is large. It should manage a sale somewhere into four figures, if I was after such a name I would check availability and prices of shorter alternatives as a benchmark.