Many people can't input their languages in foreign country's computer.
First, You have to make sure you can use computer to view your language's page.
I means if you want to install Japanese and your computer must can be show you Japanese page.
You can try to use google to finish this step.
Use http://www.google.com/language_tools? to choose your language.
If it work and you can go to step2.
Find the Language Bar.
Press Right on language bar and choose Settings
Choose your language and the Input Method than press "OK"
If you want to uninstall the Input Method just press Delete in Step4.