Depends on what is going wrong several ways.
1 Relaunch Illustrator and at the same time hold the command>option>shift on the Mac on the pc hold the Control>Alt>shift keys down while the launch process is taking place.
The other way is to trash the settings folder which is locate on the Mac in the Users/Username/Library/Preferences/Adobe Illustrator CS 4 Settings it is the last folder you trash
on the PC it is located in the C drive/Documents and Settings/Username/Library/Preferences/Adobe Illustrator CS 4 Settings or do a search for it.
It could just also be your workspace then you go to Windows>Workspace>Essentials which is the default.
Trashing the settings folder or resetting the preferences will get you back to the way you started.
A BIG 10Q again Wade.
BTW where in the world are you? You seem to be in my time zone.