My flip video won't turn off or record, won't be acknowledged by PC via USB port - seems to have frozen - screen is black but light behind it showing power is on but can't do anything with it.

it may show charged but i would get your batterty checked out.

Make sure you use a good USB 2 port and make sure your computer stays turned ON during the charging or it will not charge. The red light should stay on on the front of the camcorder while charging and will go off when charging is complete.
Try a different USB port maybe also. or if using a USB extension make sure it is a powered extension, and if not, connect the camcorder directly into a USB instead of using an extension.
My extension has a light to show that it is a powered extension.

I've got this same problem :( Turns on when I plug it in to the USB, stays on when I disconnect it but if I turn it off I can't turn it back on again. It is showing a "battery low" warning and I tried to charge it via the USB last night, but it seems to stop charging after a while and despite being left for a good time last night, this morning it is the same and I've had another battery low warning.

I've just found the full pdf manual online, and have found (on page 80) a reference to it not always behaving stably when connected via a USB hub. I'm going to try to charge it via a direct port and see if that fixes it.

Same thing happened to me. Sony refuses to acknowledge it is the update and says it is my console's failure. They want me to pay them at least $160 to fix their flawed software/hardware integration. Looks very poor upon them, and I am highly unfavorable of Sony's PS3 now. At least Microsoft was willing to own up to their flawed system when my XBox 360 showed the red ring flaw, and payed for shipment and console fix along with a nice letter of apology.
Shame on you, PS3.

UNIT: ultraHD
PROBLEM:
I just had this problem: I turned it on, started to record a video, but it hung up on frame #1, with the record red light stuck on. And I couldn't do any of the following: restart the recording, play already recorded videos, turn it off, connect to PC.
SOLUTION:
I removed the battery for about 30 seconds, then replaced it. my UltraHD flip works great now.

Just take out the batteries and put them back in. That should fix your problem. =)

I had the same problem with my flip mino HD. Here are the steps I took to fix it.

1. Adjust the power options on your laptop to ensure it does not sleep/hiberate ever.
2. Reset the camcorder by inserting a paperclip into the hole in the tripod mount. Hold the paperclip in there for about seven seconds.
3. Then immediately plug the flip into the cpu.
4. You may not see anything besides the little blinking white light on the USB arm for a while (about 30 minutes maybe) but leave it in.
5. Eventually it should spring to life and show the recharging battery on the little screen (the Flip Share program may start too.)
6. Leave it charging until the little white light stops flashing - full charge about 3 hours.
7. You can then remove the flip and change the power settings back to normal.

I was having this problem also. I originally plugged my 3 video cables into the VCR outlets in the front of the vcr. I finally turned the vcr around and found two other sets of video out plugs. One was to a dvd/dvr and the other was a vcr out. I took the plugs from the front of the vcr and plugged it into the dvd/dvr out and it worked! Good luck with your problem. Hope the resolution is just as simple.

I have the same problem and found something that kinda worked for me. Hopefully it'll work for someone else. Turn on the flip while holding down the - key. It should power up normally and allow you to view/record etc. Several videos say "Invalid Format" or something like that on the screen, but most are ok and I can record. Better than a completely dead one.