USB 2.0 external CDRW causing system freeze?

Yesterday I tried to help a friend install an external CDRW drive (a
Lite-On 5226S in a Bytecc USB 2.0 case), and a USB 2.0 PCI card (with a
Via chipset).
They both seemed to show correctly in the Device Manager, and the drive
showed in "My Computer", but when a CD was inserted, everything stopped
responding except the mouse pointer.
Control-Alt-Delete brought up a blue screen with a message saying the
"system is waiting" (I don't remember what exactly it was "waiting" for,
and don't have access to it at the moment).
There didn't seem to be a way past that error screen, so we used
Ctrl-Alt-Delete again, and it rebooted, to safe mode.
The card's drivers were installed from its own included CD.
The CDRW case's included driver wasn't installed. Windows found and
installed its own driver for it.
The computer is a Pentium 200 with Windows 98 (maybe 98SE, not sure
right now).
I had a problem like this a couple of years ago when trying to burn a CD
with Nero on my mother's computer, which turned out to be caused by a
packet-writing program already running in the background.
This time around, it happened with a store-bought, pre-recorded data
disk, and my friend's computer has never had a CDRW installed before.
Any help would be appreciated.
Thank you.