Thank you for asking. If you want to type Polish letters without installing Polish input system, you can try virtual keyboard.
1. Go to http://translate.google.com/ 2. Select the language as Polish 3. Click keyboard icon on the left bottom corner. 4. Then you can click the keyboard to type. If you want to type characters with signs, please click ‘ALT+CLTRL’ button. Then you can type them by clicking the virtual keyboard.