iMac freezes after accessing network preferences

Used my iMac this morning without any issues. However later in the afternoon, I noticed that the computer recognized only one wifi network but refused to recognize the 2 other wifi networks i have. I opened network preferences to check but the computer froze and only the movement of the mouse worked. Finally I was able to force quit the network preferences pane. But still the only function my trackpad has is to move the cursor on the screen and even the secondary wireless mouse has limited capabilities. i do have internet connection but only from the main wifi network, the secondary network still refuse to be attached even though I'm using the correct password. How can I get my computer and mouses back to full functionality? Help!!