That sounds like you are trying to use XP's native burning software. It's only vaguely comparable to DirectCD or InCD or what you used before.
I have a multi-format DVD re-writer and running WinXP Pro.
I formatted a Maxell DVD-RAM disc and was able to click & drag files in the same way as with a floppy. I have since bought an identical Panasonic DVD-RAM (non-cartridge) disc but despite formatting in exactly the same way, this won't allow click & drag option. When I do that, temporary files are copied over but Windows insists on telling me that I now need to write (burn) files to disc.
I have checked that the Panasonic disc is write-protect disabled, the same as the Maxell disc.
Am I doing something wrong ? Is anyone able to assist me, please ?