I cannot download or upgrade software from the app store. nothing happens.

App Store does not let me download or updates for my purchases. I have three updates supposedly waiting for me to download, but nothing happens when I click update all or update on each one. If Apple wants to sell apps it might be wise to solve this problem.

I have a Imac

Hardware Overview:

Model Name: iMac

Model Identifier: iMac14,2

Processor Name: Intel Core i5

Processor Speed: 3.2 GHz

Number of Processors: 1

Total Number of Cores: 4

L2 Cache (per Core): 256 KB

L3 Cache: 6 MB

Memory: 8 GB