Random crashes with flash web pages

[ColinWhite]

Hi,
I'm now running Mint 14 Xfce but I think this is a problem that occured when I ran other Linux software (am I allowed to say Mageia here?!). When I open a web page with complex graphics the whole machine freezes randomly. The mouse cursor stays where it is and nothing will get me out of it short of holding my finger on the off button for 5 secs. Typical pages that freeze are the bbc iplayer and those newspaper/journal articles with loads of moving graphic adverts around them. Youtube is generally ok (I think). It happens maybe once every 20 times or so I link to those pages. Can anyone help? It's a Toshiba Tecra A4
Thanks for your kind consideration
Colin
ps I am ever so mucha newbie!