Thanks for comments; a lot to take in. Seems AVG might be a problem,
Two points regarding AVG:
1. AVG used to be one of the better anti-virus programs, but it no
longer is, in my view. I wouldn't choose to use it.
2. I'm confused as to what you want to install--Windows 7 or Windows
8. If it's Windows 8, it comes with Windows Defender. Microsoft has
worked hard to confuse people with its names again, since Defender is
not the previous Defender, which was just an anti-spyware program. The
new Defender is what used to be called Microsoft Security Essentials,
and it's one of the best choices available. So if you install Windows
8, you don't need, and shouldn't use, any other anti-virus.
though none of this happened on my old Win XP desktop running the same
software. That passed away peacefully one day, so I had get this one.
Win 7 Home Premium was pre-installed, and although the OS repair is
backed up in a separate partition, I don't think it will capable of a
full repair. As I said earlier, this all started after the installation
of SP1, which appears to non-un-installable.
I have no intention of putting an upgrade on top of what's in here. I
reckon a complete re-format and new install is needed.
Are you having problem? If so, then I agree that a clean installation
is best. But although many people will tell you that formatting and
installing cleanly is always the best way to go, I disagree. Unlike
with previous versions of Windows, when doing an upgrade was often a
mistake, an upgrade to Windows XP or later replaces almost everything,
and usually works very well.
The only real exception is when you are having problems; in that
situation, an upgrade often worsens problems, rather than solving
them.
So unless you are having problems, my recommendation is to at least
try the upgrade, since it's much easier than a clean installation. You
can always change your mind and reinstall cleanly if problems develop.
However, don't assume that doing an upgrade relieves you of the need
to backup your data, etc. before beginning. Before starting to
upgrade, it's always prudent to recognize that things like a sudden
power loss can occur in the middle of it and cause the loss of
everything. For that reason you should make sure you have backups and
anything else you need to reinstall if the worst happens.