HDD disconnecting or restarting issue

Hi all, first time posting though I've always found a lot of answers on other stuff here before. Just not sure if the threads I've already looked at are accurate to my problem or not.

I recently bought a Seagate HDD 500gb. It's the first time using a SATA RAID device with this computer; an old ASRock K7VT4A pro motherboard. I also connected a new DVD player as a SATA RAID device with the HDD. The main system drive is an old Maxtor 40gb IDE drive.

For the past couple weeks, the Seagate drive is starting to disconnect on me while the computer is running, causing brief lockups until it reconnects, or a complete system failure and BSOD. It's monitored by a VIA RAID tool given to me by the manufacturer so it usually notifies me when it disconnects and reconnects. While listening to the drive, it sounds like it is clicking, shutting down, then restarting with an ascending whirring sound.

For all other intents and purposes, the hard drive runs great and I'm not running in to any corrupted data on it. I've also run periodic disk checks and defragments without any errors. It'll go long stretches where I have no problems at all, then suddenly it will do it to me again and again until I shut it down and leave it for awhile.

I've tried swapping out the power connector and RAID connector with the one on the DVD drive with no change, and I haven't seen any problem with the DVD drive functionality. The running temperature is about 30-35C on both HDDs while the motherboard and processor run at around 40-50C.

So what can I do to fix it? Thank you for any advice you can offer, and please let me know if there's anything I can add to clarify the problem.