After I upgraded from Win98 to Win2000, I can no longer upload photos
from my Canon A50 digital camera. The TWAIN driver causes the PC to
reboot after the 1st, 2nd, or 3rd photo. I've tried differented photo
applications with the same results. I have the latest TWAIN driver
from Canon (3.7.0), and have also tried an earlier version (3.0.1). I
have also tried different settings for the UARTS in the BIOS. I also
ran a memory test on the PC (AMD 45OMHZ with 256MB RAM) which came up
clean. Downloads worked fine before with Win98. Every other
application on Win2000 is stable, no problems.

what are u useing USB or serial? also what is your hardware in general 
this site lists a version 3.8 driver u could try that 
http://www.canon-europa.com/software/software_downloads/

ooops also this site suggets a version 3.7 . but the numbering scheme
suggets that the 3.9 version also Might work with the camera. u can
try that also http://www.powershot.com/powershot2/customer/driverdown.html
they are listed as for S110 /A10 /A20 /S40
 also Windows 2000 is a lot closer to Windows Xp so where ever u find
drivers for Windows Xp u should try them First
also before u add software . genrally(not always because some programs
are upgrades and require that u have an older version installed) its a
good idea to go to add remove programs and remove the old versions

I'm using a serial connection and cable. I don't have a USB cable for
the camera. Other hardware in the system is a standard video card, a
soundblaster compatible sound card, an internal 33.8K fax/modem, a
CD-RW, CD-ROM, two Maxtor hard-drives, and a 5.25" floppy. I'll try
the 3.9.0 driver tonight and see what happens. Thanks.

The 3.9.0 release is a USB interface, and won't work. The only RS-232C
twain driver offered by Canon is the 3.7.0. I don't want to have to go
back to Win98. Any other suggestions? If I raise the price, will that
help? :-)