Authentication window closes before I can install

I've tried to download an update for Flashplayer, and also some new software. Both times after I click "install" , the authentication window pops up as normal, but won't allow me to click "OK", then closes by itself after a few seconds leaving me unable to install the item.

Any help is VERY appreciated.

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Start with a full restart.

Could be a bad download, check your console for why this is happening, something is crashing the security. This is not good.

Oh jeez I figured out the problem and it was so simple I hate it.

My friend asked if I had any new devices hooked up like a wacom tablet or anything, and to unhook those and try installing again. I don't have any new devices but after thinking about it a while, I noticed that I leave my USB wire for my ipod connected all the time to the computer.

Sure enough, i unplugged the ipod wire and the downloads I was having problems with worked just fine.