MatureTech

I gathered that the failure happens about the same way on both drives. (1) If the optical drives start changing speed and making different noises around the time the transfer stops, and it stops in about the same place each time, then you probably just have bad media. (2) If these are PATA drives then they are probably sharing a cable to the same IDE header. In that case, a bad cable, bad header, or bad BIOS configuration would affect them both equally, the place where it stops would be more random, and you can also get "transfer complete" but the data are corrupt. Big files stress the interface so are more likely to fail than small ones.

If you have 1 GiB or more of RAM you may be encountering the infamous memory allocation troubles with W98SE. Before I sorted it out, I had similar behavior with the nVidia drivers that was not fixed by the shutdown supplement. Installing HIMEMX made that problem go away and shutdown has been clean ever since. If that's not it, then you are in for a long slog to go down the hang-on-shutdown troubleshooting checklist until the behavior changes. Good luck.

First, install the Shutdown Supplement: http://support.microsoft.com/kb/239887 That fixes most shutdown hangs. Then see if there are still problems with anything.

I had this problem with a late-2004 vintage PC. It went away when I changed the BIOS setting for the hard drives from "Native" mode to "Legacy" mode. I have two SATA hard drives and two PATA optical drives; now all are mapped onto one of two "legacy" IDE channels. Don't think ESDI_506 likes to see hard drives using non-traditional IRQs.