Q:

Automatically Refreshes Chrome/Firefox multiple times! 

Can someone let me know why sometimes Ubuntu Automatically refreshes browser and types some weird characters on shell prompt is opened. 
Is it because of memory leak!  Correct me if I'm wrong.  Because of this multiple refresh www.askubuntu.com thrown this screen.   
I was able to resolve this sort of behavior only if I close all the windows and currectly active/opened shell prompts or other applications.  
uname -a
 Linux 2.6.38-11-generic #48-Ubuntu SMP Fri Jul 29 19:05:14 UTC 2011 i686 i686 i386    GNU/Linux

A:

It looks like your F5 key got stuck.  
F5 makes your browser refresh the page and/or prints ~ into the prompt. 
Try a different keyboard and see if it resolves the problem. 