hard disk problem, clicking sound and windows problem

hi
I have a 160 GB seagate hd(sata)which is about 2.5 years old.recently my computer has started to make a clicking sound (a beep)with which the red LEDs (which i thing are associated with hd) also go on & the system freezes.this happens randomly & not while using a particular application.2-3 days ago my windows wouldn't even startup & comuter kept rebooting from the windows xp screen.I have tried to take following steps-
1. cleaned up the cabinet to ensure there was no dust
2. formatted the entire hd.
3. installed the seagate tools for hd analysis & when i performed the tests it showed "short DST failed".

according to me these are all signs of a failing hd.However,i still wanted another opinion before replacing the hd.
so,if anyone can think of the plausible reasons for above problem,please post ASAP.
thanks in advance

Well, first of all you need to tell us what is your computer specifications and which operating system you are using? Normally, if you hear a clicking sound then it surely means that your hard drive is going to die soon, but you said you hear beep sound as well, so that means you also have a problem with either your ram or your video card installed if any. First run the SMART detection tool on your computer by going into BIOS just to ensure whether it is a hard drive problem or so, and then you can try to diagnose memory test as well by downloading a tool called Memtest86, to test the ram you need to run the test full night I suppose. Refer to some guides made on beep codes from below:

http://forums.techarena.in/tips-tweaks/1098080.htm
http://forums.techarena.in/guides-tutorials/389480.htm