It has been suggested to me in order to get my scsi scanner running again (a long story), that I do a reinstall of my OS, which is NT 4.0 workstation. I've heard of an upgrade option, rather than a complete reinstall. I'm reluctant to do any of this, as for me, it's a real hassle. Could someone point me to a list of issues, such as IRQ conflicts, service pack issues, software and peripheral reinstalls, etc. that have to be dealt with in an OS reinstall? Thanks.

You can do what they call an in place upgrade. Boot to a floppy that give you CD-ROM support, change to the CD-ROM, change to the i386 directory, execute the following command "winnt32 /b". After the install (upgrade) is complete, reapply the latest service pack that you have. If you need more details, I would suggest that you go to Microsoft's web site and search the Knowledge Base with your questions.