hi all,hope someone can help here,strange problem.I have recently built a new pc and its working great except it wont install things from dvd's i put in.....games etc

It starts fine but after a little while of installing it just freezes,
my specs are:
fatality an9-32x mobo
amd athlon 5600+
3 gb xms2
fatality 7600gt in sli
160gb hard drive sata brand new
dvd rw +- brand new

i can play music cd's fine
there is no explanation of why it freezes,i have to turn the pc off manually and restart it

i have tried numerous times to install different games but it always freezes

any ideas ?
cheers
jim