When you say it clicks around 3 times does the noise happen a few seconds after power on and does the pc also appear to reboot 3 times?
- if yes and you have a cpu overclock you might try reseting to its default just to check
- if the pc boots fine (and doesn't early reboot) on power-on, once it boots to the desktop try copying various files around and listening to the HDD as it does this - same clicking noise? If yes, it may be normal platter, etc noise.
For peace of mind you might want to head on over to Seagate for drive diagnostic utilities (usually free) and also run 'Error-checking' via right mouse clicking your drive/Properties/Tools.