Unable to burn

hi, i have ripped my movie and it plays on the PC no proble. but when i open Movie Jack and attempt to burn the file. it either:

  1. automaticly jumps to 5% and then takes like an hour and then says 'buffer underun (i have tried increasing the priority of MJ to real time which dodnt solve the problem) i attempted to use CDRW’s as i dont want to wast any more CDRs (see below 4 y) and keep getting the same prob.

or
MJ doesnt go past 5% and after leaving it 2 hours i press cancel and it doesnt work, i then try shutting the PC down and i end up having to mamually restart so i can use the pc.

or

on a new CDR (tried once) goes to 22% (only tried once and thus this message appeared once) and it then gives me a error, unfortunatly i am unable to provied further information. i was wondering if any one had any ideas?
thanks soo much
chez:bow: