OK. Knowing that up front would have saved a lot of posts and replies. You also didn't say whether your friend had burned the Recovery DVD's. If he has them, he can restore the machine to where it was. That would be handy because he could find all the actual devices for which he needs drivers in Device Manager. If not, and you really get stuck, you may be able to buy a replacement set from HP for around $25 - $30. At least, that will allow you to start over. My instruction post has more info about how to prevent another catastrophy once you get to that point.
If you haven't already told HP what you're doing, do NOT keep it from them. They need to know exactly what you've got before they can give you correct answers.
I'll repost the entire text of my last post about how to do it. It's long, and I don't have time to edit it for specifics, but read through it. In fact, save it, including the links, so you can refer to it, later. You should get the info you need, but before you do, here is some specific advice:
1. Get on chat with them, instead of using the phone support. The good news is, if you get a sympathetic tech, after the obligatory warning that they don't support XP on this model, he/she may give you links to the right drivers. They did for me.
WARNING! The list and links you get may not all be right so keep searching for forum discussions, even (or especially) on HP's own forums. It took searching through several forum discussions before I finally found everything I needed.
2.
Here's a list of threads I found using a boolian search for
6735+XP+driver.
This thread looked promising.
You'll find a number of other threads listed about models DV6735 with different letters at the end. I think they refer to versions of the same machine sold in other countries. Check them to see if they also have some good info.
Here's my previous post:
I successfully removed Vista from a new HP Pavilion a1520n and got it completely working with XP. Some of what I found may be unique to HP's specific setup, but what I learned may give others some clues about what to check to install XP on similar systems. Others are welcome to add their tips and experiences.
HP and Compaq no longer provide restore disks. Instead, their systems will create ONE set of DVD's or CD's which is bonded to the machine that creates them. Other manufacturers may do the same. Therefore, before you start, make sure you have your restore disks. You may need to restore Vista for warranty service.
DO YOUR HOMEWORK. Before I started, I searched Google for the HP model number + install + XP. I found that a lot of people have tried to do it and failed on this particular machine.
1. One important thing I learned is that
Vista does some strange things to the partition table. The HP also had two, one of which was used for restore purposes. It has to go. See below for ways to do that.
2. In the CMOS, look to see if the drive is set for ATA or RAID. If it's set for RAID, change it to ATA.
I used Partition Magic, booting from a floppy, to remove them. As it was booting, the program gave me a message that something was wrong with the first partition and asked if I wanted it to fix the problem. I clicked "Yes," and that was the end of that problem. I could then remove both partitions and set up a single, active standard NTFS partition.
If your machine doesn't have a floppy, you may be able to do the same thing booting from a flash drive with the program. You can use HP's DriveKey program to make a bootable USB Flash drive and copy the command line version of Partition Magic to it. I used to be able to find it on HP's site, but
here's one link for it. The zipped file also includes basic DOS commands you may need.
Here's another link on HP's site that may do the same thing. I haven't tried this one to verify it.
A good XP installation doesn't need the restore partition, but if you want more than one partition, you'll have to set that up after you remove your old ones. Partition Magic will do it very easily.
If you don't have Partition Magic, you can try
Delpart.exe. It's a genuine Microsoft utility from NT 4 that will allow you to nuke an NTFS partition from a bootable DOS floppy. I've used it, before, and it works, but I don't know if it will with Vista's partition setup, and I don't know whether it gives you the option of deleting one of several partitions or deletes all partitions at once.
In any case, the objective is to blow off all partitions created by Vista so XP sees a completely new, unpartitioned, unformatted drive that will allow you to create a new, standard NTFS partition.
Be VERY sure you have all the drivers for the chipset and any other features on the motherboard. Find and download everything you'll need for XP, and burn it to a CD before you remove Vista. Check HP's site to look for any drivers, etc. that will work with XP. You may be able to find earlier models using the exact same motherboard that were sold with XP. If so, those drivers may work for your installation. Note the chipsets used for onboard LAN, sound, etc., and check the chip makers' sites for their chip models.
One way to find them is to check the page for the motherboard to see if they list the model or stock number. Then, go to the page where they sell replacement parts, and do a reverse lookup for the part number. It may list various models that use the same motherboard. You may also find info about the motherboard make and model by searchng for it on Google.
You should also download whatever firewall, spyware blockers and any other safety utilities you want and put them on the CD.
Then, when you install XP, do NOT activate it right away. That way, you'll be able to install your anti-virus and other safety programs before you ever hit the web to activate XP.
Norton Ghost or Acronis True Image will save your butt any number of ways. To avoid killing the machine, I installed XP on another drive and Ghosted it to the original drive only after I had it running. That way, I could test the installation before blowing off the original Vista installation.
Even if your current drive is SATA, you can build your installation on an old PATA drive and use Ghost to transfer it to a SATA drive once it's working. If you have two spare drives, you can Ghost your build as you get each step running. That way, if the next step fails, you can put it back to the last good point and try again. Running a good registry cleaner, such as Norton WinDoctor or Registry Mechanic, after installing each program can also help keep your build clean and solid.