I recently purchased a used MacBook Pro (March 2008 model) with 4GB RAM and 320GB HDD. This is my first Mac as I have been a long time PC user and felt like trying a Mac for a change. I was really enjoying the experience until two days ago while using the MacBook, it suddenly went into a white screen display with some faint coloured lines running vertically through the display. I have searched the web and saw details on resetting the PRAM and NVRAM. I have done this and the MacBook has restarted fine (sometimes) and worked for a while before the white screen reappears. Sometimes, it will not reset the problem and the white screen is there upon start-up. I hear the 'bong' before all restarts and there are no HDD clicking sounds or otherwise. In fact, when it starts normally, it works perfectly well until the next white screen.
Does the Mac warranty work worldwide and is it transferable between owners? I live in Ireland and the MacBook was originally purchased in the USA.

All help appreciated.