Hi Andy,
This is not a problem in the mouse. The COM ports are OK. This is also not a problem in the keyboard itself.
What it sounds like is happening is that you have what is called "overrun".
This can have different causes.
The most likely hardware cause is that there is something wrong with the "storage" in the 8042 keyboard controller chip on the motherboard. As I remember the 8042 can store 128 characters in a "miniram" included on the chip. If one of the last bytes is bad, this problem will only be evident under severe load. (Lots of characters in the keyboard buffer.)
Software cause, the software routine that handles the keyboard interrupts is too slow because of a polling TSR, interrupt flood, etc., or the software routine (VKD) is corrupt.
The settings in the BIOS for the typmatic rate, etc. should not make any difference because Windows is supposed to override them with the VKD driver. (The settings are under the Keyboard Icon.)
The keyboard uses IRQ 1 and I/O addresses 60 and 64, so it will not interfere with the mouse.
The more I think about this, the more difficult it is to imagine a software overload, or a flood of interrupts, bogging down a 750 Pentium so badly that this would be the only symptom.
A 386DX-25 can keep up with a fast typist, so typing doesn't take much out of a 750 Pentium.
The means that the first thing to look for is something that could cause this overload.
Regards, Chris
