The Windows.old file is helpful, but it has its problems. Some of the problems wee solved by dragging old files out of "Windows Programs 86" and dropping them into the same folder on the new version., I had to re-download two programs, but they work fine.
I had to go to another thread to learn how, but I installed Windows Media Center Player for free. Now let me explain...
Windows Media PLAYER plays DVDs for you. Windows Media CENTER connects you to a TV and makes it easier to buy and rent movies. You really don't need it. It has a big choice of films, shows, and radio stations, but you have to pay to get them. I installed it with no problem, and I see no use for it.
Because Microsoft has to pay about $800 million per year in royalties for a program that is installed on about 1/6 of all Windows computers, it will not be free after the 8 Preview Edition. Starting with the full version of Windows 8, you will have to pay for it if you want it.
Aero was reported to have been removed but will be enabled once you run your WEI, assuming your score is high enough. Its working on my PC. Its still rumored to be removed from the final release of Windows 8 though.
I have had a problem with both previews of 8 forcing me to use my password to get back in when it went to sleep. Yesterday,while exploring obscure areas of the OS, I discovered that a box had been checked stating that everyone had to use a password to wake it up.