Thanks to everyone who responded to my tale of woe; however, the new Avast Beta "almost" made it through the entire install but I received another compatibility warning at the end. It also seems like it was trying to run because I kept getting pop-up write violations and the system ended up so garbaged that I decided to go back to Win 7 via a System Image restoral. BTW, during my one-day trial install of the Win 8.1 Preview release, I found nothing that would be considered as "advantageous" over win 8.0. In fact, Microsoft has done more to "force" their will on you! Here are just a few of my findings:
WEI is gone (I'm assuming 8.1 benchmarks are a bit slower than 8.0 so they decided to remove it)
More apps have been added to the "cannot remove list"
Microsoft now requires you to establish a login to complete the 8.1 install (although some say they were able to bypass this requirement)
New start button is an outright farce! (it is nothing more than a Win + X menu in disguise)
Win 7 Recovery has been removed completely (no more System Image backups). Must use 3rd party software now.
You cannot fully disable tabbed browsing in IE 11 (option is gone)
The list goes on-and-on...
I also found 8.1 to be much more sluggish than 8.0. The new Start button is an improvement but still not good enough. I had to make a login to install the evaluation copy of Enterprise 8.0 so having to also do it for 8.1 was no surprise. I encountered other bugs that made 8.1 harder to use than 8.0 as well.
Avatar FX6327X Desktop, AMD FX-6300 6 core CPU, Radeon R9-270X graphics, 8GB RAM, Windows 10 64 bit, Bitdefender Free antivirus, MBAM on demand
HP6140 Laptop, AMD A8-3500M Quad Core APU, 6GB RAM, Windows 7 Home Premium 64 SP1, Bitdefender Free, MBAM
Google/Asus Nexus 7 tablet, Qualcomm Snapdragon quad core 1.5ghz, 32GB storage, Android 5.1.1, Dolphin browser, Bitdefender Free All machines behind a NAT router