Help with a WD5000AAKS keeps turning on/off

I have an internal WD5000AAKS HDD that worked fine until a couple days ago. Every 5 min it turns on/off , at first i thought was an internal failure with the motherboard, PSU or even drivers, then i took the drive out and set it as external drive and keeps doing the same thing.
How i can keep it on for a longer period of time to run a test and to copy important backups to another drive?

I am not aware of a dedicated procedure able to forcefully keep your hard drive active. Perhaps it would be best to send an E-mail to WD Support for recommendations. Try to prove as many details as possible as well as information related to what you have tried so far. They may contact you if they need more info.

http://support.wdc.com/support/case.aspx?lang=en