Vista buddy???
If so go to control panel and click on the "Personalization options". On the left hand side you should see "change desktop icons". Click that, recheck recylce bin and press apply and ok. It should come back.
For xp
1. Right-click an empty area of your desktop
2. Select Properties
3. Click the Desktop tab
4. Click the Customize button
5. Click Restore Default
6. Exit all windows and restart your computer
Next time post in the suggestions/help section. Thanks BAI BAI