Thanks to markw for the reply.
Andy,that's exactly what i just tried,shift all footage to my onboard hard-drive and rendered from there,no problems,so it's either the esata card,which i installed myself or the new external hard-drive.
I gonna try again now with the external drive,but using the usb connection,which seems as fast,if the render goes tits up now then i know it's the external hard-drive.
The hard drive is a seagate freeagent pro,500gb,now the thing with these seagates is,on the bottom there's a little plate which needs to be swapped over,depending on what connection is needed,one plate is for esata and usb,the other plate is for firewire,i haven't got the firewire plate.I've heard problems where this plate gets hot and doesn't stay connected,so now i'm trying to find out if it's the plate or esata card on my pc.
My suspicions are on a crap design harddrive,i'll let you all know in about 3 hours or before if render hangs again.
Dos anyone have any good reports on any make of harddrive,or bad reports on others ?
Thanks,Paul.

__________________
PMW-EX1,Manfrotto 503hdv/525,Sennheiser wireless,Sennheiser gun,Vegas Pro 8,Quad Core pc.4gb ram. Available as 2nd cam.