Clearing /tmp
Each Linux machine has its own directory called /tmp where programs keep their temporary files. Sometimes a program will act up because its temporary files have become corrupted. If e.g. Firefox or acroread is failing to work on your office computer but fine on the public computers, it is likely to be a /tmp issue.
CAUTION: do not attempt to clear /tmp completely when logged in on the console or via WineX. The "X server" needs some temporary files to work properly.
A safe way to clear /tmp is to log out completely, then log back in via ssh/putty or on a virtual console. Then type the following:
cd /tmp rm -rf * .??*