For notebook freak. I believe you know if Compaq notebook has been released newest series of CQ such as Compaq CQ-20 series, CQ-40, CQ-45 and CQ-60.

By the way there are problem with Compaq notebook series CQ-40. If you installing Windows XP, The audio may not work. The problem is come from BIOS. To make sound work well we have to downgrade to version of F.11E.

I guess if you downgraded your notebook you wont get less performance. However, there are some effect such as:

1. Indicator lights when the notebook in Charge position are not on. This is not a problem, because the battery was still charging. the indicator just showing off status only. You can make sure it with check approximately 1 until 2 hours
2. Some of the keyboard function keys that work together with the key fn does not work. According to me this is not fatal, because some of the key indeed, are not too important.
3. Can make less the “took” sound
4. The Audio can be detected.

The effects in above can be eliminated by upgrade back BIOS to F.24.

How to downgrade Compaq CQ-40
1. Make sure the bios version that you use. F.12 or F.11? If F.11 it’s mean you had been downgraded your bios. To check it you have to enter BIOS by pressing F10 while booting.
2. After the installation of windows is completed. Run file BIOS F.11E that i attached below. After extracted, run winplash.bat. then run InsydeFlash.exe
3. This Downgrade bios is only work for cq40 with intel processor
4. For more safe re Install your windows. Do not install any application if you will downgrade your bios because you can get fatal result.
5. Use adapter to downgrade bios.
6. Make sure that your cq-40 notebook has warranty.
7. I will not guarantee that you will success when to downgrade BIOS in your notebook. So think again. If you fear. I recommend you to take your notebook to HP centre.