Well I have an older Dell Demension 4500, XP professional, and...I came across an Hitachi H-L Dual layer DVD/RW...since this machine did not come with it and after installing it, I find the CD part works fine but no DVD will play, and I cannot burn any DVD also...The model number for this DVD writer is GSA 4120B and there is nothing on the Dell support site about any firmware or driver for this thing...so how can I get this thing to work properly?