ActiveX and unknown publisher HELP>???????

I just bought this Toshiba Satellite laptop 2 days ago. Now I can't see the
graphics, photos, or hear music on MySpace. It keeps telling me it can't
verify the publisher for swflash.cab. It then says "unknown publisher". I
have lowered my security settings, I have allowed shockwave, macromedia, etc
as trusted sites, I have clicked "install activeX" and still NOTHING is
working. I'm about to scream. WHY is this happening, and please tell me it
can be fixed. THANK YOU!!!