Internet Download Manager or simply IDM is the most widely used and advance download manager out there at present time, it can boast your download speed upto 5 time.
You can pause and resume your downloads, it work fine with most of the web browsers like Mozilla Firefox, Google Chrome, Opera IE and so on.
As you can pause and resume download in it then many time what happens that you are downloading a big file, and when you are turning off your computer pause that download but when you turn on computer forget to start it again.
In that case you can make IDM to download your files when you start your computer or at Windows start up.
Start your IDM and then click on Scheduler from the toolbar, and then from left sidebar click on Main Download Queue and then on right side just check Start Download At IDM Startup.
Now make sure that your IDM runs at windows start up, for this click on Downloads from toolbar and then click on Options.
Now under General Tab see whether Launch IDM At Startup is check or not, if not then check it and save it.