Funny how Opera works just fine on the "guest" account. @esteni, thanks for the suggestion but I just haven't had time or found a spare USB stick to download the old version to use in a portable fashion.

@rollobsam, not sure what you mean by BD "changed my folder settings to 'hide' various file types." Not certain about going back to Avast and may try Avira again...

Ah, @Browzer1 and @rollobsam, I am running BitDefender, plus Comodo Firewall and Malwarebytes. My wife's Win7 desktop also has BD, but it's the older version of Opera that must not have a problem with the AV software. And, @rafaelluik, I'm very careful what goes on my new baby - the only other programs downloaded so far are Crap Cleaner, Irfanview, Dropbox, Java, and WordWeb.

So, do I give up on BD? Seems a shame, Opera's shot itself in the foot by upgrading...

Interesting to read these comments, because I get the same "out of memory" message opening Opera ON A BRAND NEW LAPTOP with Windows 8.1 and 6 GB of RAM. In addition to a few apps, I've downloaded Firefox, Open Office, and a couple of others -- and everything else works wonderfully. WHAT'S THE DEAL? Maybe it's the new Opera and I should revert to the older version I've enjoyed for years on other PCs... Maybe upgrading to Windows 10 would help???????