I just finished upgrading Windows 7 Pro to Windows 8.1 Pro. I thought it was supposed to keep all files and applications, but only a few of the applications were carried over. Seems like I have to re-install most of the programs, especiall games, Office 365, and Microsoft Visual Studio. All the data, such as My Documents and downloads were kept.

Now I'm pissed -- the reason I elected to Upgrade instead of Full Install (e.g. erase hard drive and start from scratch) was so that I wouldn't have to reinstall all the apps, many of which require licence keys.

Erm.. Yep! I did it, too. It goes by faster than you think. The real kicker is gonna be running disk cleanup on all the archived win7 stuff. :) Enjoy that. If you're a drinker, grab something tasty.

I think all I have to do is delete c:\windows.old folder.

There are some other system files they keep. To make sure you get rid of it all, I would recommend you use the disk cleaner utility... but, to each their own :-/

I always tend to think of an OS upgrade as a false economy. You may save time (or not as AD has discovered) in not having to reinstall applications, but if you keep your data separate from your applications the fresh start option must surely always win out in terms of clearing clutter, speeding up the system, ironing out those usability oddities that have crept in over the months/years etc.

I find that because Microsoft keeps changing where things are put, it's much better to install from scratch than to upgrade, otherwise you end up with a mish-mash of two different directory structures.