imac blue screen

Probably should have asked this before stripping out my hard drive - when I was using safari and MS Word at the same my mac froze with the familiar spinning wheel. keyboard wouldn't do anything and mouse wouldn't , the off button didnt do anything so switched off at wall.

When I restarted all I got was as far as the apple logo then it went to a blue screen This happened loads of time so tried to reinstall Snow Leopard. It went as far as about 28 mins then stopped with a big yellow triangle. This kept happening.

Ran disk utility/repair and it kept saying 'nodes' were unused needed repair and would then report a successful repair - but when trying to load OS it still stopped at 28mins.

Now am assuming a bad sector on hD so am replacing but is this the correct diagnosis? thanks

Helps if you provide computer and operating system. However assuming you are running either Leopard or Snow Leopard and you ran Repair Disk when booted from the DVD, then yes that is the likely diagnosis.

Sorry, late 2006 model 2.16 with 2gig ram and 250mb harddrive running snow leopard.