When it just goes to the main menu, that means its not going to read the disc, unless its either a brand new one, or if you try to fix it some how.

The "sound" they are talking about is just like a little ticking sound, when my first gen. ps2 had that problem I also noticed a clicking sound comming from it, from what it sounded like to me (because I was very young at the time) was the lense eye [or something like that] hitting and skipping off the disc.
amazing what you think when your in 2nd grade