Security problem shyt

heeellloooo
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okay well idk what i did, but now this stupid balloon keeps popping up the one with the red symbol and x inside, and saying i have a security problem and it comes up every second and when it does it stops everything im doing until it goes away then a page pops up, and also when i try to download some things it says it can't because of my security policy.wth am i supposed to do, im so pissed... lol help pleaseee � :)