You're working deep into the sunny afternoon on a computer whose hard-drive has been corrupted or taken over my a virus, who knows? You're too bored to 'fix' it, so doing a system wipe and resetting it is the best way to do this. But... when you formatted and created your partition, you forgot to give enough space for Windows to be installed on the primary partition, thereby causing grief.
Now, instead of reformatting and starting again, you can use GPartED, a Linux Live CD that allows you to modify partitions without having to reformat your computer! It may not be used often, but having it on your emergency bootable USB (or CD, if you prefer CD's) is a plus, plus, plus!
And what's more, it's free, fantastic, and pure genius.
Don't forget to donate!
For more information, please go to their site @ http://gparted.sourceforge.net/