Knowing that these systems were outdated by a couple of years when we purchased them, I assumed there was likely a BIOS update available from IBM to fix the problem. Sure enough, I found a BIOS update (version X6KT190) that had been released on 1-5-2011. Our POS systems were still running X6KT170 which had been released in 2008.
Thankfully, there is an executable version of the BIOS update that can be started from within Windows, saving the need to dig out the old USB floppy drive.
After updating the BIOS, the Windows 7 Setup screen was displayed and we were able to install Windows 7 without any problem. All of the drivers also had Windows 7 support.
IBM POS 4846-545 BIOS
Thankfully, there is an executable version of the BIOS update that can be started from within Windows, saving the need to dig out the old USB floppy drive.
After updating the BIOS, the Windows 7 Setup screen was displayed and we were able to install Windows 7 without any problem. All of the drivers also had Windows 7 support.
IBM POS 4846-545 BIOS