Well if you download this little widget
http://www.dougknox.com/xp/xp_fixes.html
you can get the waste bin back onto your desktop,it seems to be a fairly common thing especially on the new Vista set up,I notice that the bin now contains a Nortons Un-erase wizard that was not there before ? me thinks that this happened after the Nortons system works download.
I would still like to know why it vanished like that,but at least my waste bin has returned thanks to that excellent little fix,anyway I hope that this helps someone in the future,never had that happen before ?