Welcome to the forums,
I certainly would not have waited that long for a DVD to burn. 3 days has got to be the record for burning a disc, and you have an amazing amount of patient..
Without any information we can only guess as to why. Please go to the sticky at the top of this forum titled, Please Read this First Before Posting
and provide the necessary information. Also complete your system specs in the Profile tab of your User Control Panel, as this may have a lot to do with why it took so long.
DVDs, which are Standard-Definition (SD) require using nothing but MPEG-2, which must meet the International DVD Specifications. So when VS starts to burn your disc it will first ensure that the video files being used meet those specs, if not it will convert or recode them. If you're using some highly compressed formats such as DivX, Xvid, MPEG-4 these are going to take longer depending on your PC's power.
If you're using hi-def video, such as AVCHD, and you don't have at least a high-end Dual core processor, if not a quad-core, then it will be a real long wait, and may not even complete.
Other things that can pose problems is mixing video files together that have different field orders. DV (avi) video uses Lower Field First, while most all MPEG-2 video files are Upper Field First.