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I just upgraded my hp dv6426us from 1gb of ram (512x2) to 4 gb (2x2). I have a vista 32 bit and xp 32 bit dual boot os configuration.

Now when I boot up xp gives me a bsod right after showing the spalsh screen. It does this in safe mode too. However, Vista works fine. The bios shows 4096mb of ram. Vista System information shows: Installed physical memory (RAM): 4.00 GB Total physical memory: 2.99 GB

I would like to be able to use xp with 4 gb of ram, or at least the 3 gb it cuts it down to (if it does.) I would not like to go back to using 1 gb. Any suggestions? Thanks!

EDIT: the bsod shows:

A problem has been detected and windows has been shut down to prevent damage to your computer. If this is the first time you've seen this stop error screen, restart your computer. If this screen appears again, follow these steps:

Check for viruses on your computer. Remove any newly installed hard drives or hard drive contollers. Check your hard drive to make sure it is proberley configured and terminated. Run CHKDSK /F to check for hard drive corruption, and then restart your computer

Technical information:

* STOP: 0x0000007B (0xBA4CF524,0xC0000034,0X00000000,0x00000000)

also, memtest86 results are no errors

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do a boot logging with the XP, then hop from the vista and read where the bootlog ends. It can help to clear the prefetch folder for boot logging. I think i have seen this with a video driver, if only i could remember, it might be a thing to disable (run in copmpatability) first to test, because of the "way" they use that memory spaces. Safe isnt very safe (even back in xo) many of the high end drivers are set to run as safe. also, You should still do a memtest86 with a boot disk, but from what your saying that isnt As Nessisary. It is likely to be a driver item, – Psycogeek Feb 8 '14 at 10:21
Ok, I will learn about bootlogging and attempt to do one right now! Thanks for the quick answer – Blaine Feb 8 '14 at 10:30
Chances are good this is fixable. If you can you want to bootlog the old way (where it worked) then bootlog with it failing, it will save a lot of time seeing what is the next item in the bootlog , where it faild. – Psycogeek Feb 8 '14 at 10:30
1. Since you boot to Vista too, you probably have bcd. Can you post here the results of BCDEdit from vista? If I recall correctly you can limit the the memory your OS can see through there. 2. Try deleting pasgefile.sys from the XP partition, and try booting - it's a long shot but doesn't hurt to try. 3. Try booting with one 2GB memory stick, and tell us how it goes. – EliadTech Feb 10 '14 at 14:29
Could you check if SATA mode in BIOS is set to AHCI. To boot xp it should be set to ATA. – ichathan Feb 12 '14 at 10:24

STOP 0x0000007B normally means "INACCESSIBLE_BOOT_DEVICE", which means that the crash on XP happens very early in the boot process.

This stop-code actually means : Something prevented protected-mode (meaning XP boot) from connecting to the device that the real-mode (meaning BIOS) passed on to protected-mode. Said device is most probably the hard disk.

One guess to the problem could be that it has to do with the BIOS seeing your additional RAM but somehow later miscommunicating with the XP boot process.

In that case, I suggest as a first step to update your BIOS from the page HP Pavilion dv6040us Notebook PC Drivers, then try again to boot. Ensure that your computer model is exactly the same as described on that page and that your BIOS is not already of that version (so as not to take this risk for nothing). Stop on the least doubt or error message, since a botched BIOS update can brick your computer.

If this doesn't help, start XP with 1 GB and fully patch it using Windows Update, including optional updates. Check in the above HP download page if any drivers are more recent than the ones Windows suggested, with special attention to the chipset and storage drivers.

If this doesn't help, setup the computer with 4 GB and try to do a Repair Installation for XP. This requires an XP boot CD, but read well on all the requirements in this article.

All backups need to be done before starting, as this kind of operations could result in a total reinstallation of all operating systems.

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about flashing the bios. The bios update says for systems with AMD processors. I have an intel core 2 duo. should I just proceed with the next steps then? – Blaine Feb 10 '14 at 23:00
NO! Get in touch with HP Support first. A botched BIOS upgrade can only be fixed by a professional. Normally the update itself will not work under the wrong conditions, but don't count on it. – harrymc Feb 11 '14 at 6:16
See if this HP article can help in locating a suitable BIOS update: Updating the BIOS‌​. – harrymc Feb 11 '14 at 7:44
yeah, I get the severity of a botched bios. I meant the steps suggested after the bios update. Thanks for the suggestion of getting in touch with hp. The only problem is that the computer is no longer under warranty. any other way to contact hp? harrymc, thanks for the artical – Blaine Feb 11 '14 at 8:40
I think warranty is required only for repairs, not to only get a download link. You could also try the HP Support Forums. – harrymc Feb 11 '14 at 10:01
up vote 1 down vote accepted

Ok, this fix was originally suggested in a comment by gladiator2345. I am now posting it as the answer since he did not.

gladiator2345 said:

Could you check if SATA mode in BIOS is set to AHCI. To boot xp it should be set to ATA

When I was changing the ram, I disconnected the cmos battery just to be safe. This must have reset the bios changing back to sata enabled mode that I forgot I had disabled to allow xp to run.
It's just like me to forget the most obvious things :P Xp sys information even recognizes 4gb of ram (although it only shows 2.64 as "available" and task manager says 3gb total. Whatever the case, performance is now stunningly better.

Thank you once again gladiator2345

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