Maybe it's related to DirectInput somehow?
It's an old DirectX API for input devices, such as keyboards and joypads.

https://en.wikipedia.org/wiki/DirectInput

It's just a wild guess, but maybe DxDiag checks for signed drivers or something, which in turn triggers the situation we see.

Unless someone knows the exact solution from the symptom, this kind of thing (a sporadic problem on 9x) is a bit trial-and-error. I'd be tempted to fiddle with COM port speeds and buffer settings, to start with.

This is a bit of a stab in the dark, and might relate to those drivers, any IRQ sharing going on? The COM port has its own IRQ?

If you think it is sound, remove the card for a bit and see if that helps.

GL

Thanks for the help. Yes, the COM port has its own IRQ (# 3) but I am not sure what kind of IRQ mess the PCI cards are creating. I have two PCI cards a Voodoo Banshee and the SB Live. After switching the SB Live to the VXD driver I also have an SB emulated card for DOS.

So yes I am suspecting something wrong with the IRQ. My BIOS is configured for PnP OS and all IRQ settings are AUTO, maybe I should start there and make sure that the IRQ is blocked in the BIOS.

I have tried different versions of Quake2 (3.20, 3.21 and 3.23) and the problem remains. I believe it must come from the mouse driver.

My mouse is a Logitech M35 serial, and it was quite difficult to find a version of the Logitech driver that gives me acces to the three buttons. Up till now I was using the driver from the Logitech Mouseware 7.2.

Is there a generic W98 driver which support 3-buttons mice?

I own a very early Logitech C7 Serial Mouse with 3-buttons. Under Windows 98SE, I use Logitech MouseWare 9.79.1 and it works great. 9.79.1 includes a driver for the Logitech First/Pilot Serial Mouse (M34,M35,C43).

Thanks, I did not know if I want to upgrade or downgrade the driver. Based on your feedback I will try upgrading.

Btw here is a repository with many different versions of the Logitech and Microsoft mouse drivers:

https://citadel.ringoflightning.net/mouse/

Today I tried various things without success:

- Diables energy management in the BIOS
- Removed ctmouse from the autoexec
- Disabled the UART FIFO for Com2
- Updated DirectX to the very latest release compatible with Windows98 (dated of 2006 !)
- Tried several Logitech Mouseware drivers, decided to sick to the Windows Generic mouse driver
- Reseated the mouse and screwed it in place
- Tried several versions of Quake2 and other games (like Duke3D in Windows)

... none of this helped. After a while the mouse will just freeze. It happens mostly in games typically Quake2, but sometimes also when doing normal stuff like using the file manager. The DirectX update might have improved things a bit, I was able to play a Quake2 for full hour befoe the mouse froze, before it was rare to go beyond 15 to 30 minutes max.

I have an other serial mouse that I need to test. Also I will change from Com2 to Com1 (need to find my DB25 to DB9 adapter first).

I am confident this is a software issue because under DOS I have no problem.

Apprciate any suggestion...