hi
http://support.microsoft.com/kb/810869
there is also an automatic fix-it at the above microsoft link
To fix this issue in Windows Vista, follow these steps:
- Click Start, and then click Control Panel.
- Click Appearance and Personalization, click Personalization, and then clickChange desktop icons.
- Click to select the Recycle Bin check box, and then click OK.
http://itsvista.com/2007/01/itsvista-tip-19-restore-your-vista-recycle-bin-icon/
- Right-click on your desktop and choose Personalize
- Click on the Change Desktop Icons link in the upper left hand corner
- In the Desktop Icons Settings window, check the Recycle Bin box and clickOK
and see if you are interested in these articles to stop you accidently doing it again in the future
http://www.howtogeek.com/howto/windows-vista/disable-deletion-of-the-recycle-bin-in-windows-vista/
How to hide the "Delete" command from Recycle Bin context menu in Windows Vista