Alright, I am using the school's comp to online, but unfortunately the admin account has been locked. I cannot install anything ( yet ). But after some googling, I managed to find a way to install the flash player for Firefox.
1. Download the xpi package from http://fpdownload.macromedia.com/get/flashplayer/xpi/current/flashplayer-win.xpi
2. Rename the attributes to .zip.
3. Copy the files
flashplayer.xpt and
NPSWF32.dll to
%APPDATA%\Mozilla\Plugins\ where
%APPDATA% is the folder which holds your applications profiles and settings. (You can open this folder simply choosing "Start → Run → Type in %APPDATA% → OK")
4. Run Firefox if you havent. Restart if you used it earlier.
5. Enjoy..