This happens when FM is running a script... and it sounds like there is a problem in your script that is causing it to get stuck. You see the blinking period (.) next to the Command symbol that is now your mouse? That's actually telling you that to stop the script you need to hold the Command key and then push the period key. Your mouse should return to normal.
Further to Ethan's point, you need to investigate what is causing the script to hang (eg. a loop with no exit), if indeed that is the cause.
I'm not quite sure how to end my script. I'm new at scripting and obviously this one causes a problem. I have since deactivated it.
Do you know how I am to end a simple "Perform Script" Script?
There is the "End if" option, but I don't have any "if"s factored into my script and I can't type "End".
I am using the script to sort and show only relevant records in this given layout... so it is a Script Trigger set to run upon OnRecordLoad and OnLayoutEnter.
My guess is either you're performing a find on an unindexed or related field and the find is taking a really long time or you've got some OnModeEntry script trigger that triggers when you do a find, performing a find, triggering a find, etc.
Why don't yu try posting your script, or even your file?
Adding to what DavidJondreau said.
How many records are you doing this Find on? Is the database hosted with a FM Server?
For bigger Finds I sometimes use the script step Go to Related Records instead.
Also, there is the Exit Script script step, but it does not appear that it would be of any help here.