@Cookiie
Your probably Infected. Try this.

AVG(free) might be able to fix it. Be sure to update it before you scan your computer: AVG Free Advisor: AVG Anti-Virus Free, then follow the prompts.
Once AVG has fixed the Problem you can delete it if you want to.
Hope this Helps.

@Simon
Try updating Java to 1.6.7. See Link

Remove All Java versions installed (via Add/Remove Programs) before you install the latest Version. (Download the JRE Offline Installer)
Java SE Downloads Fifth one down. ( 1.6.7 ).
Hope this Helps.

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