I write a dvd in night and see in morning that my cd/dvd drive is missing in my computers drive {laptop hp pavilion dv2500}

Hi. I think you could try updating the drivers for your DVD drive or by deleting the upper and lower filters on the registry so that we could verify if this a hardware or software issue. follow this instruction on deleting the upper and lower filters on the registry:

1. Click the Start button and click in the Start Si write a dvd in night and see in morning that my - 2_bing.gifimg src="/uploads/images/2_bing.gif" alt="2_bing.gif" class="h_mi" />.
2. Type regedit, and then press the <Enter> key.
   Note: The User Account Control window may appear. If so, click Continue. The Registry Editor window appears.
3. Click the arrow next to HKEY_LOCAL_MACHINE.
4. Click the arrow next to SYSTEM.
5. Click the arrow next to CurrentControlSet.
6. Click the arrow next to Control.
7. Click the arrow next to Class.
8. Click {4D36E965-E325-11CE-BFC1-08002BE10318}.
9. In the right-hand pane of the window, click UpperFilters.
10. Click Edit on the menu bar.
11. Click Delete. The Confirm Value Delete window appears.
12. Click Yes.
13. In the right-hand pane of the window, click LowerFilters.
14. Click Edit on the menu bar.
15. Click Delete. The Confirm Value Delete window appears.
16. Click Yes.
17. Click File, and then click Exit.
18. Click the Start button.
19. Click the arrow to the right of the lock icon.
20. Select Restart.