Option 1:
If you start experience so many
system crashes that you can't take it anymore then Rebuilding
the Desktop may solve your problem. Most of the time it does.
Boot up the computer while holding
down Command and the Option keys. Remember that
rebuilding the Desktop file removes any information you may have
in the Get Info boxes.
Option 2:
Zap your PRAM! A special part
of RAM, called PRAM, controls the settings such as the clock
and Desktop settings. This area of RAM might become corrupt.
You can "ZAP" the PRAM to reset it to its correct settings
by performing the following:
Return to the Desktop
From the Special Menu, select
Restart.
Press and hold the Command-Option-P-R
keys all at once (you might need someone to help you...)
Release the keys when you hear
the system startup sound at least 4 or 5 times.