External Hard Drive turns off randomly for no reason

[Clearwater]

For the past few weeks (or months, even), my external hard drive has been randomly been turning off whenever it's connected up to my laptop, and I can't quite fathom why. It only does it very occasionally, but if and when it does it at a very bad moment (Such as when I'm in a Steam game which gobbles up all my RAM), some of the games I download through Steam have their files corrupted and I have to start from scratch.

My external hard drive is a Toshiba External USB 3.0 500 GB, I keep it plugged in to my one of my laptop's 3 USB 3.0 ports (I unplug it when I turn the laptop off), I've had it for a few years now, and it's never had any problems, even when I still was using it on my crappy old desktop computer. It doesn't have/use a power adaptor (Meaning all I need to do is just hook it up and it turns on). Looking at the cable  I'm more than confident that it hasn't frayed in any way (I keep the cable as straight as possible).

When the hard drive turns off, the blue light on it briefly turns off for a split-second and I hear the 'USB Device Disconnected' system sound, then about 2 seconds later, I hear the 'USB Device Connected' system sound and the Autoplay menu appears. If I've got Steam running, I get the 'steam.exe has stopped working' error message (Windows 7 claims it's an APPCRASH instance).

I've also made sure that no settings related to the system turning off/suspending any external USB devices after a period of idle time has been turned on as well. We've also tried the hard drive on my brother's laptop for a few hours, and there hasn't been a single instance of my problem that has happened.

Anyone know why this is happening? In case it helps, my laptop is Windows 7 Ultimate SP1 64-Bit, and my laptop model is a Fujitsu Lifebook A555.

Edited October 8, 2016 by Clearwater

[CrypticQuery]

Have you tried plugging it into the other USB ports on your laptop?  It could be that one of the ports is shorting or otherwise receiving intermittent power drops.  Given that it works on all other devices fine, I doubt the issue is with the HDD or its power/data cable.

[Sideways]

When your HDD shuts off and your laptop tells you it's disconnected and reconnected, you should go look at your event logs. It might give you a clue as to what's happening.

[fanfictiondreamer]

Hm...it seems like we're all having trouble with our computers lately. My internet has either paused or lagged and that problem is not limited to one website. There must be something wrong with my internet connection or there's something in my laptop that's causing this. Now that I think about it, the same thing has been happening with a lot of my other programs, not just the internet. I'll need to talk to my mom about this.