need help with my macbook pro

ok so, my macbook pro has been acting pretty stupid lately. first off, something started taking up all my start up disk space. I backed up all my files and managed to stop the leak. Then a few weeks later my computer froze so I had to force it to shut down. now it wont boot up. It stays on a white screen with the apple symbol and the loading wheel. Then the screen goes black and starts bringing up all these white texts. I got the install disc to run but when it gets to the "select destination" it doesn't show any destinations. now do I go to disk utility and "erase" the the hard drive or do I "restore" hard drive?