Ive tried ...........
different - known good hard drives.
different - known good memory
Internal dvd rom - with the rec dvds in it
external dvd rom - with the rec dvds in it
recovery partition - f10
recovery dvds - I chose [x] verified when burning them.
Ive also tried a MS OEM DVD of the op sys Vista Home Premium - and it refuses the serial number from the back of the laptop ! So disappointed with that :-(