Computer can not open browsers

My graphic design class is running osx Leopard and I felt like using my extensions on firefox for the class. Portable Firefox would not open from my drive. I then stopped trying seeing as how it would just not pop up on the dock. I now can not open ANY browsers on the computer. I am of course not an administrator on this computer. But when I told my teacher, he didn't really worry about it and brushed it off. I need to open the browser to compose messages for wordpress in this class. I am hoping it is just a file that needs to be deleted that is not letting another browser open when using firefox portable. This happened two days ago so I know that restarts etc. will not work. Thanks for any help.