unable to view internet videos

That's a somewhat ambiguous result, but let's assume that there was an improvement in safe mode. No crashing, at least.

Please read this whole message before doing anything.

This procedure is a diagnostic test. It won’t solve your problem. Don’t be disappointed when you find that nothing has changed after you complete it.

Third-party system modifications are a common cause of usability problems. By a “system modification,” I mean software that affects the operation of other software — potentially for the worse. The following procedure will help identify which such modifications you've installed. Don’t be alarmed by the complexity of these instructions — they’re easy to carry out and won’t change anything on your Mac.

These steps are to be taken while booted in “normal” mode, not in safe mode. If you’re now running in safe mode, reboot as usual before continuing.

Below are instructions to enter some UNIX shell commands. The commands are harmless, but they must be entered exactly as given in order to work. If you have doubts about the safety of the procedure suggested here, search this site for other discussions in which it’s been followed without any report of ill effects.

Some of the commands will line-wrap or scroll in your browser, but each one is really just a single line, all of which must be selected. You can accomplish this easily by triple-clicking anywhere in the line. The whole line will highlight, and you can then either copy or drag it. The headings “Step 1” and so on are not part of the commands.

Note: If you have more than one user account, Step 2 must be taken as an administrator. Ordinarily that would be the user created automatically when you booted the system for the first time. The other steps should be taken as the user who has the problem, if different. Most personal Macs have only one user, and in that case this paragraph doesn’t apply.

Launch the Terminal application in any of the following ways:

☞ Enter the first few letters of its name into a Spotlight search. Select it in the results (it should be at the top.)

☞ In the Finder, select Go ▹ Utilities from the menu bar, or press the key combination shift-command-U. The application is in the folder that opens.

☞ If you’re running Mac OS X 10.7 or later, open LaunchPad. Click Utilities, then Terminal in the page that opens.

When you launch Terminal, a text window will open with a line already in it, ending either in a dollar sign (“$”) or a percent sign (“%”). If you get the percent sign, enter “sh” (without the quotes) and press return. You should then get a new line ending in a dollar sign.

Step 1

Copy or drag — do not type — the line below into the Terminal window, then press return:

kextstat -kl | awk '!/com\.apple/{printf "%s %s\n", $6, $7}'

Post the lines of output (if any) that appear below what you just entered (the text, please, not a screenshot.)

Step 2

Repeat with this line:

sudo launchctl list | sed 1d | awk '!/0x|com\.(apple|openssh|vix)|edu\.mit|org\.(amavis|apache|cups|isc|ntp|postfix|x)/{print $3}'

This time, you'll be prompted for your login password, which won't be displayed when you type it. You may get a one-time warning not to screw up. You don't need to post the warning.

Note: If you don’t have a login password, you’ll need to set one before taking this step. If that’s not possible, skip to the next step.

Step 3

launchctl list | sed 1d | awk '!/0x|com\.apple|edu\.mit|org\.(x|openbsd)/{print $3}'

Step 4

ls -1A /e*/mach* {,/}L*/{Ad,Compon,Ex,Fram,In,Keyb,La,Mail/Bu,P*P,Priv,Qu,Scripti,Servi,Spo,Sta}* L*/Fonts 2> /dev/null

Important: If you synchronize with a MobileMe account, your me.com email address may appear in the output of the above command. If so, anonymize it before posting.

Step 5

osascript -e 'tell application "System Events" to get name of every login item' 2> /dev/null

Remember, steps 1-5 are all drag-and-drop or copy-and-paste, whichever you prefer — no typing, except your password. Also remember to post the output.

You can then quit Terminal.

Please read this whole message carefully, especially the warnings, before doing anything.

The changes to your configuration suggested here should be considered provisional; they may not solve your problem, or they may remove functionality that you find useful. If a third-party system modification that you want to keep is causing the problem, seek help from its developer.

WARNING: Back up all data now if you haven’t already done so. Before proceeding, you must be sure you can restore your system to its present state, even if it becomes unbootable. If you’re not sure you can do that, STOP — DON’T CHANGE ANYTHING. If you’re dissatisfied with the results of the procedure suggested below, restore from your backup. I will not be responsible for the consequences, and I will not help, if you ignore this warning.

You should either remove or update the following system modification(s), if an update is available from the developer:

VMWare

and definitely remove at least the following:

† If2k (see www.internetfilter.com)

† DivX

† Norton Utilities

Cooliris

Facebook Video Chat

Whatever you remove must be removed completely, and (unless otherwise specified in this message) the only way to do that is to use the uninstallation tool, if any, provided by the third-party developer, or to follow his instructions. In some cases it may be necessary to re-download or even reinstall the software in order to get rid of it. I can't be more specific, because I don't install such things myself. Please do your own research.

Here are some general guidelines to get you started. Suppose you want to remove something called “BrickYourMac.” First check the developer's website, say www.brickyourmac.com, for instructions. If you don’t find any, email the developer. Failing that, download BrickYourMac.dmg and open it. There may be an application in there such as “Uninstall BrickYourMac.” If not, open “BrickYourMac.pkg” and look for an Uninstall button.

If you can’t remove the software in any other way, you’ll have to erase your boot volume and perform a clean reinstallation of the Mac OS. Never install any third-party software unless you're sure you know how to uninstall it; otherwise you may create problems that are very hard to solve.

WARNING: Trying to remove complex system modifications by hunting for files by name often will not work and may make the problem worse.

I recommend that you never reinstall the modifications marked with a dagger (†) above, if any. If your problem is resolved after uninstalling all the above modifications and rebooting, but you still want to use some of those not marked with a dagger, you can experiment with putting them back, one at a time, testing carefully after each step. Keep in mind that system modifications may be incompatible with each other or with future Mac OS updates, so it may not be clear which one is at fault.

If you still have problems after making the suggested changes and rebooting, post again. Remember: if you don’t like the results of this procedure, you can undo it by restoring from the last backup you made before you started.

Everything I can tell you about uninstalling system modifications is in my last message. You should be asking Facebook how to uninstall its software, not me. I wouldn't know. I don't know of any utility that would help.

TucMac, I had this problem for many months until I had to upgrade the NVIDIA drivers for my mac (MacPro 3,1 late 2008). After that all isues were resolved. It seems that when I upgraded to Mac OS Lion the drivers were not "acceptable" and youtube and many other video applicatiosn did not work properly. Please check your video card drivbers and see if they are up to date.