HDD spinning delay

Hi to everyone, Im from Argentina so please sory for my English.

I instaled windows 7 64bits a month ago and I experience this since then.
I have 2 HDD (non partitioned) I have windows 7, all the programs and all my data in the 500GB one(C:). And I use a secondary hdd (D:) of 160GB only to back up my main data.
Both are SATA (the 500GB is SATA II, and the other is SATA I)
Everyting is working fine, all drivers instaled and updated, the PC in a fliying plane (jajaja)
But I think the secondary hdd is not spining until I have to use it, for example when I enter to My PC and select D: drive the disc make a short noise an after a couple of seconds the files and directories of the drive apears on the screen.
Since I use this hdd only once a month for back up only, that doesnt bother me.
The problem is when I use Photoshop CS2, after it finish load it seek something in D:, again the short noise and a couple of seconds of the photoshop unresponsive.

I tested the drive with HD-tune, speed seems to be right (60MB/s and 13ms seek) and SMART values ok.

Is the hdd dying?
or for some reason is sleep and wake up when I try to acced it or some program does.
There is any windows configuration to keep the hdd alive while the PC is on?

Thanks in advance for your input!

Check your Power Plan (under Power Options in Win 7). If you choose to change advanced settings, you have an option for hard disks (2nd option I believe) where they can turn off if idle.

Thank you!
Problem solved. Was the default power plan that put the hdd to sleep after 20 min.