How can i stop a script from disappearing after execution?
as the last line make it ask for user input. it depends on what version of the program you are useing.
it is probably raw_input then just make a statment to exit, like
print “press any key to quit”
stop = raw_input()
if stop = * print “quitting”
what ever version of python you downloaded will be at c:python#.# open you c drive and then open your python folder or directory. there will be a doc folder. open that and you will find among other things a tutorial. if you are on windows you may only have a python . chm file…click on that and it’ll be there. stuff like that is very early in the tutorial…which is actually a good tutorial. i wish blender came with something like that.
Sorry i mean from disappearing in blender.
Is there maybe a line i could attach to the main function or something that prevents the
closing of the script GUI window after the execution so that you can use it again?
Well, it is a matter if the script is designed to run several times or only once… In the latter case, you may re-work a little the script to make it run s cycle quiting only by pressing a specific key… Most simply, this can be done following the ideas of posting #2 above 
Regards,