From Winclone Software:
WinClone will clone Windows onto a different volume on the fly (which means that you needn't stop your work) and make sure it is bootable. Therefore, you have dual Windows on your PC. Then you can use them separately, for example, one for work, the other for program testing, or just for a complete backup in case you ever have a problem with Windows.These dual Windows are independent, in other words, they do not affect each other, and even one is infected with viruses. You can also just use the clone as Windows backup. When the current Windows has problem running or is infected with viruses, you can immediately boot into the Windows clone, and then continue working.