apt-get system reinstallation

[Bart Silverstrim]

Is there a simple way to try a "reinstall" of everything currently 
installed on my system?

I have 2 Ubuntu 8.04 systems, one where youtube videos crash Firefox 
constantly (flash problem?) and the other doesn't seem have trouble 
playing flash videos. So while the latest Firefox and flash plugins from 
the repos may have troubles, it may be a combination problem of some 
kind on the one that is causing issues?

I didn't know if there was a simple way to try an in-place reinstall of 
software to see if it was a linking or dependancy issue that could be 
causing flash videos to keel over on the one system.