Emacs on Ubuntu. DIsplay issues: text displayed over other text

I'm a newbie to emacs, just starting to like it - but today upon start up the following issue has rendered it unusable.

Problem: When I move the cursor forward some,开发者_运维技巧 but not all, characters are rendered unreadable. The next letter on the line is displayed over the previous character, not replacing it but displaying both in the same place at the same time. Obviously i can't show this as then text editor on this site is functioning correctly.

A few of examples of what I've tried so far, with no effect..

1- restarting gdm

2- apt-get install rxvt-unicode - to check if it was a problem with xterm

3. dpkg-reconfigure emacs

4. completely removing and reinstalling emacs23 along with .emacs config file.

Converting Ben's comment to an answer to get it from the unanswered questions list:

It appears to have been an issue with the font. If I do the following it works:

1. type- xlsfonts -into the terminal and get a list of the fonts available.
2. choose one of the mono-space fonts (e.g. r14) and check by running: emacs -fn r14 myfileName

To make this default go to options menu within emacs then -> Customise Emacs -> Specific Face -> and type: 'default' and click 'set for future sessions'.

Today I faced the same issue. Installing the latest snapshot instead of stable branch solves it:

sudo add-apt-repository ppa:cassou/emacs
sudo apt-get update
sudo apt-get install emacs-snapshot