BSOD on Windows XP while installing with External USB

I hope you all have read the title properly here so I am quite sure that you all have got a hint of the problem that I am facing right now. Actually I am attempting to downgrade my computer from Windows 7 64 bit to Windows XP Professional 32 bit, so that’s what I am planning to do this with the host drive removed from the computer. However I was very unlucky here I was not able to do that at all. so I did changed the BIOS setting to IDE and tried using the original disc windows xp pro and while doing that I get a stop error 0x0000007b. So what is that it is causing problem here can you please explain it to me I need some suggestions for the same.

Why are you trying to install the windows with the external drive just place the drive inside and then continue with the installation actually one though t that I would like to share here is that installing windows on external drive is totally unadvisable so better don’t repeat the same mistake again and continue with the installation by keeping the drive placed in physically, so that’s what I am trying to say here hope you have got the necessary answer for the problem.

I have got one method for you, see what you have to do is clone your windows 7 and put the image onto your external drive make sure that you have the disk partitions made in the system so it always becomes a necessity to keep a back up in one of the partitions. So once you had the necessary backup and then you can certainly go ahead with the installation of the xp in the drive. If you cannot perform this operations then the above solutions is nearly perfect for you, so give it a try my friend it will work out for you.

Let me tell you that installation with the external drive is not at all possible so thats why I am asking you to not to work on it it will be of no use at all. so that’s what I am trying to say here, well in some bios setting there is an option of booting directly from the external drive while in some it is not there, as such I don’t think it is present in your system so better look after it, it will be better if you do not go ahead with the idea that you have in your mind that will be certainly helpful.

Ok thanks for all the help that you have given here yes it certainly seems to be a very difficult process according to me so that’s what I am trying to say here. Putting an iso file in the disc and then giving it to write certainly seems to be an easy option for me so thanks for letting me know about that as well, so that's what i think i will go ahead and work on it i am praying that it will prove beneficial for me so that's what i want to say here. Lets hope for the best.