HDD makes wierd noise at power on

The HDD that houses my OS makes a weird noise upon powering on. It occurs when the drive has to spin up it sounds like it's spinning up but the sound is..... Off. Kinda like a old CD-ROM drive when the disk is spinning really fast. The sound is not continual it only happens at spin up from a power on state and for one second it does not occur when reboot is initiated.

I've already taken the liberty to back up all HDDs in the computer as I am not taking any chances also I've done a short SMART self test using Seatools and it passed all tests (It's a Seagate drive) will do a long and short test as soon as I can get Seatools for DOS also the drive does not appear to have any read/write problems and works perfectly fine afterwards.

I did check the drive in Crystal Disk Info last night and it reported a yellow caution alert for Reallocated Sector Count. However when I turned the PC on a hour ago and checked again the Sector Count had not increased. This drive would be a good two years old as that's how old the system so I wanted to know if this is something I should lose sleep over or if it can be ignored. I can RMA it as I should be under warranty but I'd really like to avoid that if possible. The HDD power on noise started in March.

The model name is ST500NM0011 if it helps.

 

Just tested the Seagate drive in Seatools for DOS. It passed the long and short DST as well as the Acoustic test.

 

Sounds like the motor in your HDD is going bad. At the minimum you should back up your data. If it starts taking longer to spin up, or the noises get progressively worse, a complete failure is probably in your near future.

 

Whenever the value of the "Reallocated Sector Count" is NOT zero, the drive believes that the media is failing AND you have a brief window of opportunity.
Get a copy of RoadKill's RawCopy ( http://www.roadkil.net/program.php/P22/Raw Copy )
Get an identical or slightly larger replacement hard disk drive.
Use RawCopy's physical drives to copy the failing drive to the replacement and then swap out the bad drive.
P.S. This is easiest done on another PC with the failing drive and the replacement connected as drives 2 and 3.