WinLED

As modern computers and laptops are becoming sleeker, thinner, and even more stylish, less and less are still using the so-called hard drive activity light or HDD LED, as it's also known.
This little light might be of great help if, for example, your computer becomes unresponsive and you want to check and see the drive activity. It may also prove its worth by helping you better decide if you should force your computer to shutdown or not.

Unobtrusive HDD activity monitor that lives in the system tray

Thankfully, you can try WinLED, a tiny Windows utility that, true to its name, adds a minimalist hard drive activity LED to your computer's tray, thus making it possible for you to keep a close eye on your HDD's actions.
It can be deployed in a matter of seconds and with the least amount of effort thanks to an intuitive, wizard-based installer, just as long as you make sure that .NET Framework 4.5 or later is present on your computer's system.

Simple, stylish, and unexpectedly configurable HDD activity app

Quite surprisingly, this nifty utility is a bit more than it might show at first. Hover over its tray icon with the cursor, and you're provided instantly provided with information regarding the reading and writing activities of the HDD.
Even better, right-click its tray icon and you're provided with a few configurations options as well. You're able to handpick which partition of the HDD the app should monitor.
In addition, you can configure the app to display the activity via a LED or via a Trend Chart, as well as choose from 3 different color sets for each (especially handy for users with impaired vision or color vision deficiencies).

Brings a bit of retro feel to your modern computer's tray

There you have it - a simple and efficient tray utility that should bring a bit of comfort to users who are used to knowing when their hard drive is active, all while taking into account possible color-related vision deficiencies.