I'm not joking, but Google searching all that stuff might be a lot of work and, still, might not really tell me what is going on.

I just tried a little, and it
looks like Google is working better than I expected and more
like you suggested:

(1) At

http://indianexpress.com/article/technology/technology-other...

is

"You’ll still be able to run XP computers and install past updates. If you need to reinstall XP from scratch, you can do so if you still have the discs that came with your computer."

Well I do have the original install disk and
the codes. Hmm ..., but my install disk is an
'upgrade' from Windows 2000, so if I lost
my boot drive, with three partitions, one for
2000 and two for XP, maybe I would need to
install 2000 before installing XP. I have the
2000 media and codes but would wonder if the
Microsoft authorization server would still be up.

(2) For my most important software tool, my favorite
editor KEDIT, the first search result was from Wikipedia and clearly stated that KEDIT will run on Windows 7 64 bit (presumably both 7 and KEDIT will run on a 32 bit processor).

So, good news so far.

I intend to buy another computer fairly soon. Then computer A will do its backup to disk space on computer B, and B to A. Main point: If computer A fails, then I still have computer B still working and with all the data on computer A. So, fix (or replace) computer A, copy the data back from B, and continue.

The reason I got a copy of Windows 7 is that it will be the OS I will run on my next computer, computer B. Then with computer B just sitting there, I will be able to do experiments in installation, configuration, system management and administration, etc. while computer A still has access to the Internet for Google, MSDN, various fora, etc.

Then via the Microsoft BizSpark program, I will install on computer B, on its own disk partition, the most recent, appropriately sized, copies of Windows Server, IIS, SQL Server, etc. That will be my Web server for my startup.

For now, my computer A with XP I hope will keep running until I get computer B running. Why? I'm concentrating on the rest of the software development for my startup and don't want to take a detour into more 'system management'.

Generally, though, the main way I have in mind to solve
problems of software installation, configuration, compatibility, etc. is just to have a second computer (so that I will still have a working computer) to run experiments on until I discover what the situation is.
E.g., I suspect that the way a high end user of, say, SQL Server gets installations done is just to have a computer with an appropriate version of Windows Server and then just install over and over until everything is smooth, document is, and hopefully automate it.

Net, I need a second computer. Soon.

I have a copy of Acronis 'True Image' or some such;
maybe I should dig into it and get a 'true image'
of my Windows 2000 partition in case it needs to be
there in case the boot drive fails and I need to
reinstall my Windows XP 'upgrade'. Then I will be able
to reinstall my NTBACKUP image of my favorite XP
boot partition. I.e., my computer has three hard drives,
one for boot partitions, one for disk to disk backup, and
one for the real work. I'm well enough backed up that if
any one disk fails I will still be able to recover
(at least if I grab a copy of the Windows 2000 partition).