Admitted, when it comes to burn CD/DVD in Windows 7 I still prefer using the 3rd Party tool, like ImgBurn. But if you only want to burn CD/DVDs from the ISO/IMG files you have already in file, like those you download from the Technet Subscription website, using the built-in Windows Disc Image Burner is deadly simple and you should use it.
Simply right-click the ISO/IMG file you wan to burn from, go Open With, and choose Windows Disc Image Burner.
Put in the blank disc, check Verify option if needed, and click Burn. A little while later, a disc will be burned.
How easy it is!