wateronsand wrote on 2025-10-23, 23:10:

Hi all, […]
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Hi all,

Dell Dimension XPS R350, BIOS A13
Microsoft IntelliMouse PS/2

When booting in pure DOS I can't get any mouse drivers to recognize the mouse. I've tried all the various permutations of:

• Win9x (DOS 7.1) BootGUI=0
• DOS 6.22
• Microsoft MOUSE.COM 8.2
• CTMOUSE 1.9.1, 2.0A4, 2.1B4
• Not reserving any memory addresses or IRQs in BIOS.
• Both with and without HIMEM/EMM386
• "Plug and Play OS" in BIOS both on and off
• "Legacy USB support" in BIOS both on and off (no USB devices are connected but since I understand this feature makes USB mouse/keyboard appear as PS/2 and I'm out of other ideas, why not)

MSD and MSINFO32 both show no conflicts on IRQ 1 or 12.

...but as soon as I start Windows 95/98, the mouse works fine and shows in Device Manager as the PS/2 Mouse Port.

Please save me from this madness

If you check the device details in Windows 98, can you see what resources the mouse is using?

SOLVED: I had read about some BIOSes not initializing the PS/2 mouse port on boot. Retroweb has the previous (A12) BIOS labeled as "Last good known BIOS." I flashed that and the mouse now works in pure DOS.

Thanks @douglar for the reply!