Dual Boot Installation with Windows 7 and XP

Yes yes, not entirely meaningless of course, but what I'm trying to understand here is how exactly the computer knows whats written inside the boot file, when I don't see any definitions which would assign letters to partitions inside of it and the assignments can be completely unique for each Windows on the same machine. So in other words, the way I understand it now, the boot file must be read with the help of some reference file, because let's say
device partition=F:
path \Windows\system32\winload.exe
means something entirely different when viewed by this or that operating system, or not? How does the boot file know which letter assignments are to be used so that its contents make sense?
You mentioned "Secondary drive letters". Does that mean there are primary ones too? Do those determine what the contents of the boot file say?

Hi there.

After reading this guide and others on the web, I finally managed to get dual boot Windows 7 and XP working. Like to share my experience with others here.
I am using Windows 7 RTM and Windows XP SP3 Install CD, with a new unformatted 1 TB HDD, and a backup WinXP running on a different HDD.

Attempt 1:
I used my old XP installation to partition my new HDD for Windows 7 and XP partitions. I then rebooted from Win 7 DVD and tried to install Win 7 on the pre-formatted partitions. No go. Win 7 won't install unless I delete the existing partitions and recreate it from scratch.

Attempt 2:
I removed all partitions and let Win7 DVD create a 200GB partition (via Advanced > New..) . Win 7 created the System Reserved partition (100MB) and and the OS partition. (Note that at this time there is no unallocated 1MB partition in front of the System Reserved Partition.) I then started Win XP CD, created a new partition 200GB partition using WInXP CD (text based menu) and started the installation there. Upon rebooting, I get the following message.
"Error Loading Operating System"
Using the Win 7 DVD startup repair tool does NOT resolve this issue. When I booted up using my backup OS on another drive, I noticed 1MB unallocated space in front of every partition on my new drive.

Attempt 3:
I restarted and assigned a drive letter to "System Reserved". Does not help. Same error and mysterious unallocated 1MB space appears before each partition after Win XP CD partitioning and formatting.

Attempt 4:
Stuck at the previous issue for several hours, I decided to try another approach. I deleted all partitions on my new drive. I started WIn 7 DVD, and this time let Win 7 OS partition take my whole 1TB drive. (emulate pre-install conditions) After WIn7 installation is done, I booted in Win 7, went to Disk Management and re-partitioned the drive to free up 800GB of unallocated space. I then rebooted and started my WinXP installation CD. Upon entering Win XP CD text-based partitioning menu, I noticed a WinXP CD detected a 1MB unallocated space before my "System Reserved" partition which wasn't there in previous tries. I let XP take the remaining 800GB space and started XP installation. Upon rebooting, instead of "Error Loading Operating System", I get...
_
...(a blinking cursor.)
Sensing some hope, I put in my Win 7 Installation CD and ran startup repair tool. Upon reboot, my system was able to boot into WIn 7 OS again.(But no dual boot menu).
From then on I just installed EasyBCD Download EasyBCD 1.7.2 - NeoSmart Technologies, created a WinXP entry, and rebooted. This time the dual boot menu came up, I selected XP option and the XP install continued from there.Success!

Attempt 5:
I varied Attempt 4 by pre-creating the XP partition beforehand in Win 7 Disk management Tool (as I couldn't resize the XP partition to the size I want after Attempt 4), loading Win XP CD, reformatted that partition (as I heard XP NTFS not truly compatible with Win7 NTFS), and installed XP into that partition. Re-run startup-repair tool, and the repeated the rest of the steps. This method also works. Seems like as long as the unallocated 1MB partition was created by Win 7 Disk management tool, the startup repair tool works. However, If you use the Win 7 DVD (Advanced > New..) partitioning method, the unallocated 1MB space will not be created at the front of disk and Win 7 startup repair tool will fail.

I then spent the other 1/2 of the day figuring out how to get Kubuntu booted as the 3rd OS, but that's a story for another day.

Hi all, I would like to thank you VERY much! i spent about 4 hours trying to be able to boot back into windows 7 after installing XP on a partition until i came here and it was a quick and easy fix! thank you once again.

So I have Win 7 64 installed on my C drive - a 1TB Raid 0.
I installed Win XP Home 32 on a different 750 GB Non raid

I tried to boot to Win 7 after XP install. Failed. I didn't find this forum, but instead, put the Win 7 CD in and recovered my Win 7 MBR through that.
I'm now unable to boot to Win XP even though I manually adjusted the MBR in Win 7 via the command prompt.

When I try to load Win XP at OS select it tells me Win XP MBR is corrupt and to put in the disc.

So...which steps should I follow to finish this process Win 7 side only?
I installed Easy ECB, deleted the manual entry I established in the MBR for Win XP and used Easy to create a new one.

Do I have to copy anything over to my Win XP partition to get this to work? Am I missing any steps? The XP option is pointed to the correct drive I think. In my win 7 setup it shows as drive E, though in the XP setup it shows as drive D (and My 7 setup shows as drive C across both.)

Hi binkky,

It seems you had the 7 HD attached when installing XP.

The XP bootfiles would be on the Active partition on 7 HD.

You should be able to add ntldr to 7 bcd - try pointing Easybcd at the System, Active partition to do that ( sounds like that would be C).



Then click Add Entry, then Save.

Remove any incorrect ntldr entries with Easybcd as well.

I think that did the trick. I tried that out before your post, and I just had my wife test it at home (god bless remote access).
I was just able to select either or in boot up and it booted successfully to both. This is a fantastic forum and I'm going to do all I can to never lose it. Great stuff guys, thanks so much!

You're welcome - glad it's working for you.

LordFett said:

When I install Win7 and select XP from the boot loader my computer reboots. I tried repairing my XP install since I couldn't boot from it any longer. I ended up having to reformat, it was suggested to install 7 from within XP. This did not work, because I have x86 xp and x64 7.

I am trying again using your tutorial (which is how I did it initally, lets hope it works this time).

I have 3 hard drives, one for XP with a 10gig partition for a page file, one for 7 with same 10 gig for page file and a final drive I store non-program data on.

If XP first then 7 install doesn't work this time I'll try 7 then XP and as a last resort I will use the boot loader from SUSE 10. Never used it with 2 windows installs though.

Has anyone else had dual boot issues with a 64 bit and non-64 bit version?

Sorry to reply to an old post, but just so others know it is possible to use Win7 x64 and XP x86 as a dual boot. Got mine setup last night, they are on the same HDD. Everything seems to be working fine. :)