blank web sites

Explorer starts to open a site ,top menu appears and then vanishes and page is blank , no problem with "flat pages" ,only where the frames are
i have got firewall but it just has happend recently before was fine I deleted cookies,history and other temporary files ,no results.I would appreciate an advice (please do not be too proffesional otherwise I do not understand.Thank You

it could be that your firewall has blocked it because it was an advert, i use norton firewall and that blocks a lot of adds on web sites, check your firewall logs for any leads