Insomniate

There are a lot of users who like to leave their computers on during the night to perform complex or time-consuming tasks, like graphic rendering or downloading of large files.
If you are one of these people and you want to make sure that these tasks are not suspended when the PC enters Standby mode, you can try Insomniate, a minimalistic solution with a basic GUI.

Portable app for keeping your PC awake

This application is a portable one, meaning that you do not need to have it installed on your computer to benefit from its functions.
Moreover, you can carry it on a removable flash drive and run Insomniate whenever you need to prevent the current computer from entering Standby or Sleep modes.

Set the countdown timer for keeping the PC awake

A handy function of this utility is that it includes a timer that allows you to choose for how long you want the PC to stay awake.
In other words, you simply enter the number of hours, minutes, and seconds and then start the timer and you are done. You can just leave the PC complete its tasks while resting assured that it does not enter Standby mode.
On the downside, it does not come with a scheduler, so you cannot schedule it to keep the PC awake on a regular basis, nor does it allow you to define intervals.

Unobtrusive, runs in the system tray

Another nifty feature of Insomniate is the fact that it runs in the background, without bothering you from work or taking up space in your taskbar or desktop. Once you configured the previously mentioned timer, you can minimize it and it automatically goes to the system tray until the time runs out.
It does not require a lot of resources, so chances are that you might even forget it is a currently running program.
All in all, Insomniate can come in handy to all users who are looking for a simple way to prevent Sleep and Standby modes when they no longer work on their computers.