i installed 11.04 (my first experience with ubuntu, please go easy on me..) only a few days ago after Vista crashed on my computer. i installed flash and all the correct plug-ins as far as i can tell because the videos begin playing just fine. but when watching youtube videos one after another, or an episode on hulu or anything, without fail after around 15 minutes (the first time; every following time i turn the computer back on afterwards takes less time to shut down) spontaneously i see a black screen with grey writing that i can barely read before it just shuts down. this happens in Firefox and Chromium. please help, this is so frustrating.
It will be very difficult to say what might be wrong. You have not mentioned any thing about the H/W you are using. Desktop PC or laptop, Graphics card etc.
One cause of the shutdown might be over heating. Playing videos using Flash is a quite processor intensive work. Normally playing video heats up the CPU more quickly. One thing you can do is check the CUP temperature while you are watching Hulu.
Install lmsensors : sudo apt-get install lm_sensors Check the temp: sensors
If you see your cpu temp is shooting up high while playing the Hulu, indicates you have some problem with your cooling system. Check it out, let us know so that we can debug the issue further.
Hold up - maybe the sensors are right. Is your laptop full of dust or does it have a broken fan? I am amazed at how much junk can get in the fans and make them not able to cool down the system like they should. Do you have a can of air to clean out at least some of the dust? (if your system is clean as a whistle, then sorry for the rant....) Bob from Arlington