Dear sir i have hp compaq cq40 -120Ax laptop . Now i want downgrading my os vista to xp but when i try to install xp there is a blue screen message 0x0000007b is apper . How can i solve it please help me.

If you are downgrading your OS from Vista to XP, you have to repartition & reformat your HDD before fresh installing Win XP OS. BSOD is due to drivers installed which is not compatible to you hardware,

You have to check if any drivers for XP is available for your laptop model @ HP Support
You can use the "Service Tag" for your search to locate the exact model.

Hope it helps.

<span style="FONT-FAMILY: Arial; FONT-SIZE: 10pt; mso-fareast-font-family: 'Times New Roman'; mso-ansi-language: EN-AU; mso-fareast-language: EN-US; mso-bidi-language: AR-SA">You need to download the drivers from the Compaq/HP WEB support/download page. Make sure you select your model laptop and the XP Windows version of the drivers you require and install them. Click on this link to download the drivers: -<br style="mso-special-character: line-break" /></span><br /> <span style="FONT-FAMILY: Arial; FONT-SIZE: 10pt; mso-fareast-font-family: 'Times New Roman'; mso-ansi-language: EN-AU; mso-fareast-language: EN-US; mso-bidi-language: AR-SA"></span> <br /> <span style="FONT-FAMILY: Arial; FONT-SIZE: 10pt; mso-fareast-font-family: 'Times New Roman'; mso-ansi-language: EN-AU; mso-fareast-language: EN-US; mso-bidi-language: AR-SA"><span style="FONT-FAMILY: Arial; FONT-SIZE: 10pt; mso-fareast-font-family: 'Times New Roman'; mso-ansi-language: EN-AU; mso-fareast-language: EN-US; mso-bidi-language: AR-SA"><a href="http://www.compaq.com/country/cpq_support.html">www.compaq.com/country/cpq_support.html</a></span></span><br /> <span style="FONT-FAMILY: Arial; FONT-SIZE: 10pt; mso-fareast-font-family: 'Times New Roman'; mso-ansi-language: EN-AU; mso-fareast-language: EN-US; mso-bidi-language: AR-SA"><span style="FONT-FAMILY: Arial; FONT-SIZE: 10pt; mso-fareast-font-family: 'Times New Roman'; mso-ansi-language: EN-AU; mso-fareast-language: EN-US; mso-bidi-language: AR-SA"></span> <br /> <br style="mso-special-character: line-break" /><br /></span>

you mean you need to downgrade your computer from Windows Vista to XP?
if so is the case, you need to go to the BIOS in the Boot menu, select IDE from ACPI.
put the boot option to boot from CD first or disable Boot from hard disk.
then you will be able to downgrade your computer from Vista to XP.

You can install XP over Vista if you want. You should be able to get the drivers as well. I believe the instructions for this (if you need them) can be found at HP (Compaq).

Be very certain this is what you want to do before you start. Are you having trouble with your present configuration? It may be easier to fix your trouble than change your OS.

You may want to go to www.pcpitstop.com and have your computer scanned for problems before you start. This is a free service. If you go ahead with the install, go back to PC Pitstop and have it scanned.

This is a little confusing. What exactly are you trying to do?
Are you trying to wipe Vista off and install XP? If so, you must first reformat the hard drive and then install XP

try to install the driver for touchpad, if the same check the hardware.. or try return to vista if working properly it means some problem for os xp.. because you downgrade the system...

hp company advice all user to do not downgrade but we can we use xp. the problem only not compatible some drivers


thanls

You need to download the drivers from the Compaq/HP WEB support/download page. Make sure you select your model laptop and the XP Windows version of the drivers you require and install them.

Use this link to download the drivers
http://h18000.www1.hp.com/cpq-country/cpq_support.html

Compaq Presario C791TU Notebook PC
Microsoft Windows Vista
http://h10025.www1.hp.com/ewfrf/wc/softwareList?os=2093&lc=en&dlc=en&cc=us&product=3739739&lang=en

its the feature of microsoft that it would not let install win xp on a computer with vista. what u can do is completely format the computer and use bootable xp cd and install .

Similar Problem already discussed here