windows 7 burn to DVD issue

I have watched the Microsoft video on how to burn data to a blank DVD. I have done a search "windows 7 dvd burner does not work" (this is on google.ca: windows 7 dvd burner does not work - Google Search -- probably google.com gives the same list) and looked at all the links. They all say the same thing, which used to work for me. Put a blank DVD in the drive, select the second burn option (the one that produces a DVD that can be read by other computers, not the first option, which is the one that causes the DVD to be like a memory stick), and drag the files to be copied to the window. That used to produce a list, which, when it finished, I could then click on "burn" and the files selected would be burned in a few minutes. Now when I drag or copy a list of files to the appropriate window or to the drive icon (D: on my Windows 7 computer) nothing happens. That is, no list of files appears. The only way I can copy data files to a blank disk is to first format the disk and then drag the files over. With this method they copy fine but doing so takes upwards of half an hour instead of the few minutes it used to take. I haven't changed my system since the last time I did this and it worked properly. The only major change that I can think of is I replaced McAfee with Microsoft Security Essentials. Any suggestions? Thanks.

Because of issues with the built-in burning included with various versions of Windows I keep getting Roxio Easy CD and DVD Burning for my computers, about $30 at Wal*Mart, never have a problem. And I tend to use only CD-R, DVD-R and DVD+R discs [Recordable, once], don't have a pressing need for the RW [ReWritable] discs. Usually R discs don't need pre-formatting like the RW discs do, probably format on-the-fly or as needed before writing files.

Thanks for your response. My disks are all RW but these are the same that I used when it was working before. Rather than a $30 solution I can always use the formatting route. I'd just like it to work the way it used to, which is the way it's supposed to.

Which service is responsible for copying files to the DVD drive? That function doesn't work for me. Thanks.