thanks every1 for the replies, I tried the following things but none of them worked - 1. Switched the RAM modules 2. Used them one by one 3. Set the Defaults in BIOS. One thing I failed to mention, the hard disk and Cd ROM are set as Seconday Master and Secondary Slave respectively. (Actually , I am fixing this PC for a friend who has messed it up) Would that have any effect on the installation ? Should I set it to primary and then try again ?