Maybe you could be more specific. Tell us the Motherboard, the CPU speed, amount of Ram, kind of hard drives. Did you put this unit in yourself or did it come with the machine? Is it showing up as UDMA-2 and DMA has been selected? Did you use the Nero software that came with the unit or are you trying to burn your disks with something else? Does it just stop or does it crash the system when it stalls?

i have 250 RAM and no i am not what came with the burne i am using using nero 6.
it frezze the computer after 13%

Right click on My Computer. From the Menu, choose properties. From the window that pops up, click on the Hardware tab. Then click on the button that says Device Manager. Another window will pop up. Click on the "+" sign next to icon which has the text IDE ATA/ATAPI Controllers. You should see a Primary and Secondary IDE Channel. Right click first on the Primary channel and choose Properties. Then click on the tab that says Advanced Settings. You want DMA if available. Do the same for your Secondary Channel. If either said PIO only (depending on whether or not you have an old CD Rom drive), this was probably your problem. You will have to reboot for it to take effect. (If you have never played with this before, just look and don't change anything, just report back what it says.)
 
While you are there, you can check on your CD/DVD drives to see if there are any conflicts. Click on the "+" and then right click and select properties on the drive you want to see.
 
If you have 256meg of Ram, this is probably just good enough. Try defragmenting your hard drive however.
 
Usually, a manufacturer supplies you with the Software for the drive. Actually, I think Nero is supplied with the Yamaha drive. This is supposed to one of the faster drives on the market and they may have a special configuration of Nero for it.