Can't Download AOL Instant Messenger

I just received a new hard drive, and obviously had to re download everything. I tried to download AOL Instant Messenger, and when I go to install it, it tell me there is no default application to use to install it, and that I should choose one. I never came across this problem with my old hard drive. Could it be a malfunction of the hard drive? Also, does anyone know what application to use to install it? THANK YOU!