This is information from my own experiences and those of many others, based on an Intel platform and XP 32bit. XP 64bit is untested and probably has a lot of missing or unsupported drivers. Most of this should work for AMD XP 32bit, but there will be some differences in drivers, such as the chipset. There are currently no specific links to these drivers in this post, but should be elsewhere in this thread.

I do not make claim to all this information myself, nor do I claim that everything will work for you. Proceed at your own risk. If you need a more detailed guide, check the post here:
http://forum.notebookreview.com/show...&postcount=141

Note that I think the above guide is quite old. So use it when the following doesn't make sense, and then carry on with this guide.

1.Backup the c:\swsetup directory to a DVD while in Vista.
2.Go here: http://downloadcenter.intel.com/Prod...=2973⟨=eng and select your XP OS version. Download the following software:
-32-bit Floppy Configuration Utility
-INF Update Utility - Primarily for Intel® 4, 3, 900 Series Chipsets
-Intel Matrix Storage Manager (optional but recommended, see very bottom of post)
-Intel Graphics Media Accelerator Driver if you have Intel Graphics (see step 8)
3.Extract the 32-bit Floppy Configuration Utility zip file somewhere
4.Use nLite to slipstream XP SP3 and the textmode SATA driver extracted from the above zip file into a new XP install. The SATA driver is located in iaAHCI.inf and is called ICH9M-E/M SATA AHCI Controller
5.Install XP
6.Install Intel INF Update Utility, downloaded from step 2
7.Reboot
8.nVidia now officially release laptop drivers (recommended):

http://www.nvidia.com/object/notebook_drivers.html Alternatively, install modded nVidia driver: http://www.laptopvideo2go.com/forum/...x.php?f88.html using the modified inf file. If you have Intel Graphics, install the Intel driver you downloaded from step 2
9.Reboot
10. Either: [a] Download wifi 5100 driver from here (Intel® PRO/Wireless and WiFi Link Drivers-Only for Windows XP is the driver only. Alternatively, you can instead get Intel® PROSet/Wireless WiFi Connection Utility for Windows XP which includes the drivers and a management utility (not really needed)): http://downloadcenter.intel.com/Prod...=3062⟨=eng
Install wifi 5100 driver by extracting the zip file and running iProDifX.exe, or running the exe straight, depending on which above download was chosen
or [b] if you have the Broadcom b/g WLAN, try this driver:

ftp://ftp.hp.com/pub/softpaq/sp41501-42000/sp41680.exe
11.Run Windows Update (Custom update) and install drivers for Realtek Network card, Agere Modem, Touchpad, .net 2.0 (under optional software). Do not install the IDT audio driver from Windows Update. See below for audio solution. To enable middle mouse click by using both left and right buttons at once, see: http://forum.notebookreview.com/show...&postcount=523
12.Reboot
13.Run swsetup\drivers\misc2\setup.exe to install the card reader driver
14.Run swsetup\drivers\misc5\setup.exe to install the finger print reader driver
15.Reboot to enable the FPR driver (software to use the fingerprint reader for XP now available for purchase, DigitalPersona Personal 4.0)
16.Install this IDT audio driver: ftp://ftp.hp.com/pub/softpaq/sp41501-42000/sp41693.exe Before rebooting, read here and fix the "pop" noise due to powersaving:

http://forum.notebookreview.com/show...&postcount=509
Reboot. If you mute button does not work correctly, try the following steps:
http://forum.notebookreview.com/show...&postcount=387
You need to make sure the process stacsv.exe is running after installing the drivers and rebooting.
To fix the orange mute issue, see this post (CAUTION - this involves editing the registry which could break your windows install if you do something wrong):

http://forum.notebookreview.com/show...&postcount=354
If the mute button fix above does not work for you, after the registry change try to run "stacsv.exe -r" from Program Files\IDT\WDM folder.
To add steromix to the drivers (CAUTION - this involves editing the registry which could break your windows install if you do something wrong):

http://forum.notebookreview.com/show...&postcount=431
17.Reboot
18.Manually install drivers for:
HP Integrated Module (bluetooth)
Multimedia Controller (TV tuner)
Audio device on HDA Bus (HDMI Audio)
by selecting "Install from specific location (advanced)" then "search for best driver" in DVD. Insert a DVD that contains the "swsetup" directory.
19. CIR Remote driver here: ftp://ftp.hp.com/pub/softpaq/sp41501-42000/sp41661.exe
To remap the buttons, read here: http://forum.notebookreview.com/show...&postcount=512
If that doesn't work, read About the CIR Remote driver: http://forum.notebookreview.com/show...&postcount=373
More info and driver here: http://forum.notebookreview.com/show...&postcount=399
20. Drive Guard driver has been reported to work for some people, but not others. http://forum.notebookreview.com/show...&postcount=530
21.(CAUTION - read all of this step before proceeding! Only do this step if your brightness controls do not automatically work after installing XP.) Update the BIOS to F.0B A or later. This is sp40822 available here: http://h10025.www1.hp.com/ewfrf/wc/s...roduct=3767378
Do NOT install this BIOS update if you already have this version or a later version. The update software will inform you of this fact. To ensure you have the correct BIOS update software, I strongly suggest you do NOT follow the link above but rather search for your specific dv5t model and proceed to the drivers update page from there. On your specific driver page you want to look for the driver called "WinFlash for HP Notebook System BIOS" or similar. Note that the linked update should work, but since this is dealing with a BIOS update I do NOT want to responsible for any errors. Proceed at your own risk. The BIOS update causes the Fn- brightness controls to work under XP. This is an old step now, and most new laptops should already have this BIOS version or a newer one, if there is a newer one.
22. You should now have a working XP install. Some of these drivers might be a little out of date, but work. You can check this thread for driver updates:

http://forum.notebookreview.com/showthread.php?t=338874

Notes:
1.If you did not save the swsetup folder first, you can download any drivers or software required via HP's site.
2. You can only select HDMI audio as a source when an HDMI cable is connected to both the laptop and a TV/audio device. Otherwise the HDMI audio source option is not visible.
3. To remap keys, such as the QuickPlay button, check this post:

http://forum.notebookreview.com/show...&postcount=776

Issues:
1.ProtectStore HDD software doesn't install under XP. HDD protection only works for some people using above driver
2.nVidia driver from laptopvideo2go may have sub-par performance when powermizer is enabled. If you find this happens to you, disable it or use the official nVidia drivers - they appear to work ok for me with PowerMizer enabled.

Optional:
1.Quicklaunch (Fn keys and the touch media keys work without this software installed), but it can still be installed but may break somethings such as the remote.
2.QuickPlay (need an older version if you want this software, and may need to use the registry hack trick to install. Swsetup version will not install under XP, even with the registry hack install trick). I suggest getting a better free media player such as the KM Player, Winamp, VLC, mplayer and/or Foobar 2000.
3.Quicktouch does not install under XP and is buggy and useless. For a nice free OSD alternative, I suggest 3RVX available here: http://matt.malensek.net/software
4.Intel Matrix Storage Manager - From what I can gather this just installs the Intel SATA driver, which is already installed by slipstreaming it with nLite. This package in addition installs a monitoring console of somesort, so it might be worth while as it may indicate errors to you. Otherwise not needed. Use latest version from Intel's site.
5.HP Wireless assistant if you need to enable/disable bluetooth and wireless separately, otherwise just use XP's built-in wireless assistant