Problem with USB keyboard from PS/2 keyboard

Hello:

I recently got a Saitek Eclipse USB keyboard to replace and old PS/2 keyboard that I had for years. The USB keyboard works fine but if I try to start the machine without the PS/2 keyboard still attached, I will get nothing but a black screen at startup.

I can start the machine with just the PS/2 keyboard and it will work, but not the other way around and I would like to finally detach the PS/2 from the system.

I went into the BIOS and allowed USB keyboards and legacy device.

The motherboard is a GIGABYTE GA-P35-DS3L LGA 775 Intel P35 ATX.

I am wondering if I will have to uninstall the PS/2 from device manager, but I worry about doing this because I might not be able to get back in as I cannot if I leave the PS/2 unattached to the system on startup.

Thank you in advance.