you can press the function key if it didn't work you can plug an external mouse and reinstall the driver in case you don't know how to do this you first need to delete the current driver to do this right click on windows logo press device manager click mouse and other pointing devices delete the driver but be careful don't delete the driver of your external mouse then download the mouse driver you want from here https://www.asus.com/Notebooks/Eee_PC_1201N_Seashell/HelpDesk_Download/
and i think this will fix any problem you have
please tell me if this work and tell me if it doesn't
thanks,