Vizio XVT3D474SV questions

Hi, I just bought a refurbed Vizio XVT3D474SV a couple days ago, and have a few questions.

I got a 7/11 upgrade, then a 12/11 upgrade the first and second days, with the latter one giving me Youtube among others in the VIA, however list the web Widgets (I think that's what it's called, only had it a few hours before it was gone). Any way of getting that back?

I heard a later upgrade was supposed to turn on the 3 USB ports. Putting a thumbdrive in with images, etc. does nothing. Not even a USB input option under Menu or Input, however the thumbdrive lights up that's it's on.

I was watching some 3D content on the Youtube App (mostly movie trailers and movies videos). Some of the music videos had a very bad constant flicker on the screen, not in the glasses, but could see it only wearing glasses. The screen would keep flickering even after exiting the video until I'd pick another video than OK. Some videos looked great, and the 3D effect was overwhelming. I noticed most of them I had to use the SBS setting. How do I get rid of the flickering? I don't have a 3D blu-ray player, or cable TV/satellite, and no 3D content I see on OTA.

I have my PC in the VGA input. I can only choose 1920 X 1080, would rather use 1360 X 768 resolution as some other TV's offer with a PC as easier to read text, etc. 1080 makes text pretty tiny at normal TV viewing distance without having to tweak the heck out of the PC, and still can't get everything set.

Is it normal for the 3D not work with the PC VGA input, even though I selected a Youtube 3D video? Says "3D not available in this mode".

Anyone have success on pairing the TV's Bluetooth with their smartphone? Phone and TV don't discover each other, would be nice to hear calls over the TV, or use some phone things on the TV.

Thanks much.

I have another concern too, In PC mode, I get a variable hum when I use my PC in the TV's VGA input. An open window will produce some white noise noticeable if I turn the TV's volume up to 40+ (out of 100). A full screen window will produce more hum. Opening another app will add. Closing the window minimizes the hum again, The hum is similar to CRT TV's when sometimes there was a text banner on the bottom of the screen during a commercial and it would buzz. If I use WinAmp or another audio app to listen to something, the hum doesn't go away when I close the app. If I press Audio reset in the TV menu, all is quite again, even if I put the volume up to 100, until I open another window or app. Depends on what it is on how bad the hiss/hum, sometimes not very noticeable and sometimes noticeable with the volume 20+. This is using the TV's own speakers. I tried all kinds of settings in the Audio settings. In the EQ, Rock and Pop make the hum worse, Classical less, but then I see Classical uses flatter settings.

I just did some more tests, disconnected the PC audio in, and a hiss still there when I turn up the volume, but no additional hum on top of that when I open a window or app. I also found out that resetting the audio doesn't get rid of the hiss/hum, it just rests the volume level down to about 18 where it sounds muted. The mute button also mutes it, but back again when mute is turned off.