Thanks for all the support and help everyone.
I know I didn't update this thread right away...so please forgive me for my laziness.
There were 2 problems:
1. Garberator was stuck because it wasn't used for 2 years
2. There was a metal piece inside the garberator (just like what Trouble mentioned above)
Bill (Aquaman) came over with a "key"/wrench thing and he used it to turn the blades from the bottom. Once that was done, the humming noise was gone, but when I turned it on, there was a LOUD noise...as if it was broken. He put his hand in and took out a metal piece...almost like a nail and once that was out, the garberator worked fine.
This also in-turn fixed the dish-washer because the water can now go through freely.
If I only took the initiative and did this early, I could have prevented the massive damage to the floor (which still needs to be fixed).
Thanks Bill for your help. Very reliable and jolly guy