Could my HDD be broken??

[katboi]

A few months ago i got a new 750GB HDD, everything was fine until recently;

Once every few times I boot (like 2 in 5) the PC will restart once i get into windows and once it turns back on it will nolonger recognize my SATA HDD.

I added a second HDD (with the ribbion cable, not the sata), with vista, and it dosen't seen to have a problem.

How do i find out what is happening?

I've run scanning software (multiple, including AVG, malbytes, adaware, spydoctor, etc) and got nothing.

Its weird cause it only happens every now and again, what could it be?

Thanks in advance to anyone who posts with help.

 

[geofelt]

Check that the SATA cables are secure on both ends. They sometimes come loose.

 

[katboi]

Ya, The SATA cables and power cables are the first things I checked, I replaced the SATA with a new cable and still have the same problem, tired all the different SATA ports on the MOBO (ASUS M2N SLI Deluxe)

I'm still clueless.

 

[katboi]

I did some reading and I wonder if it could be due to my AVG? (found an article here: http://hothardware.com/News/Oops-AVG-Virus-Scanner-Crashes-Computers/)
How would I check?

I did CHKDSK and Defragmented, but still no luck.
Anything else I could try?

 

[geofelt]

The HDD manufacturer will usually have a diagnostic program that you can download and run.