Hello Lenny - welcome to PSG
If your Brush Size pointer is suddenly replaced with a Precise pointer, check to see if the [caps lock] key has been turned on accidentally. This key allows you to switch from Brush Size to Precise when depressed. If this isn't the case you may need to throw out your Preferences file and then restart the application.
In version 5.5 open the Photoshop Application folder and delete the Adobe Photoshop Prefs file located in the Adobe Photoshop Settings folder. This will force Photoshop to re-create your preferences. Then restart Photoshop and more than likely all your problems will be solved.