I run Win7 Pro SP1 on two computers, a Dell 8700 desktop with 12gB memory and an HP Elitebook 8770w with 16gB memory, both with I7 processors and 64 bit OS. I'm not a gamer but instead a heavy Dragon user for reports I write and didn't like it when Dragon would slow me down while it completed some large memory-hogging task. My question is this: why is it that I can sometimes preview pdf files in Explorer and sometimes (far more often in fact) cannot? And previewer is always mute with pdf files when they aren't displayed. It never tells me it cannot or why not. Same question about previewing Word files in Explorer, where it will simply say "this file cant be previewed" or "no preview available". Then, when I try the Word file&folder window, those preview just fine. However, often, the Word previewer won't work either. It comes back with "an error in MS Word previewer". It's hard to believe that MS would make such a visible and frequently used function so unstable. It's not just a bad OS file, I don't believe, because both computers have the same problem yet were bought almost a year apart from one another, each directly from the mfr. And a previous Dell XPS L511z bought almost 3 yrs ago had the same problems as well. Perhaps it's my folder settings...though I don't see how. Help, if there is any to be had on this problem, would be greatly appreciated.