Usually if the sound is: tick, tick, pause a sec, tick, tick
it's the heads returning to home, they will sometime park themselves to verify alignment. This is bad, it means the drive is noticing that the heads are moving off track while reading data, usually heat causes this, or bumps while running. Laptop drives experience this a lot when failing.
Run the manufactures diag disk and it will tell you for sure. The os error logs are usually less specific, and lots of times smart errors aren't even reported, course you have to make sure it's turned on in the bios.