W-7 and w-xp on same comp

Yes you can but you need Install XP first then you should Install Windows 7 b'coz if you will Install Windows 7 first on your Computer then you will not able to Install Windows XP ..........


so you should Install XP Primary then Windows 7.

If you do as Puru... wrote, you will be able to boot either OS but you will not be able to boot from either disk. You will always start the boot sequence (well, after BIOS) from the drive on which you installed XP. A boot manager will come up which will ask you which OS you want to run.

IF you actually want to be able to remove one drive and still boot from the other, you have to remove the XP drive before installing 7.

But if you do this, you have to pick what disk to boot to earlier in the sequence. It's a trade-off; if I didn't have a meeting I'd try to make the two options clearer.

I installed win7 after winXP on the same drive. Had a issue where it would only boot to win7 so what I did was edit my bootmgr from win7 and copy the edited version to the c:\ on the winXP and that was it it always asked me which system to start at startup.

EDIT:
Let me clarify 1 drive with 2 partitions, so it's like 2 drives with 1 partition each.

"Ahh, there's the rub." There is a slight but very significant difference between one drive with two partitions and two drives with one each. I don't mean to pick on you, accolite, it's just an opportunity to make things clear.

Very, very coarsely, bootup has four steps. The code for them lives in different places.

1) The BIOS, which resides on a chip on your motherboard (assuming you don't have a UEFI mobo), establishes basic communication with your disks. BIOS: Basic Input-Output System. The BIOS then chooses, either from a list you gave it or by its own arcane methods, a disk to boot from.

2) The BIOS reads the MBR (Master Boot Record) from that disk. No matter how many partitions there are, there is either zero or one MBR; it is disk-wide. The MBR points to a small program that is used for the next step of booting.

3) The program that the MBR gave access to chooses a partition to run from, and uses that partition's PBR (Partition Boot Record) to load yet another small program, named the something-or-other.

4) The something-or-other starts loading the OS.

So if you have one drive with two partitions, I can guarantee that you only have one MBR and your "system partition" will be on that drive. (that's another topic - why does Windows boot from the "system partition" and load the system from the "boot partition?") But if you have two drives, whether you have one MBR or two, whether the BIOS has to pick which disk's MBR to use or the choice comes later in the process, depends on how you did the installation.

And how you do the installation should depend on what you want to do. If you are migrating from XP to 7 and will eventually remove the WinXP drive, you want to be sure that you can boot from the MBR on the Win7 drive. If you are going to keep both, well, no big deal if the boot process starts on the XP drive and then goes over to the Win7 drive.

I will edit this if I find my link to the really excellent and exhaustive article that I use for reference on the boot process.

=================================

That said: My personal choice, if not my advice, is to have every disk be independently bootable. That way, if my XP drive is corrupted, I can still boot Win7. When I put an SSD in my XP machine and installed Win7, I removed all my HDDs until after the Win7 install.

Hey no problem, I see your point.

Thanks for the info, so far I have only done one drive with 2 OS and a second as data storage, but not 2 drives with an OS on each.