USB wireless keyboard not always detected by Win2K

(Topic originally posted as part of "USB Keyboard works in BIOS but not in Windows 2000", but I think it deserves its own life... I hope you agree and can help!)
I use a Microsoft Wireless Optical Desktop 700 that has a shared USB Receiver for mouse & keyboard. Mouse always works, but Windows randomly fails to detect keyboard. No error messages appear.
Keyboard always works in BIOS and always works when booting into Linux on same machine. Keyboard batteries are good, keyboard-to-receiver distance OK. Even when no text appears on screen in Windows, the Receiver LED flashes as keys are pressed.
After having shut system down and removed AC power altogether then rebooting some time later having changed nothing in the meantime, keyboard may or may not work when Windows loads.
If keyboard doesn't work, the fix is to unplug & replug the receiver into the same or any USB port.
Replying to the original topic, pkellmey thought that the keyboard might be using the registry to load a specific driver. This seems logical to me under the circumstances in my case.
I use the drivers built into Win2k for mouse & keyboard and have tried reloading these with no improvement. I have had no luck in googling for a "stand-alone" driver.
Even when the keyboard isn't working after a reboot, Device Manager shows all HID & USB drivers OK.
I have removed all other devices from all USB sockets except my printer (whether this is switched on or switched off at time of boot makes no difference to the keyboard behaviour).
pkellmey suggested "try removing everything from your startup and adding the apps back in until you find the culprit process that is killing it or change the order of the startup applications (it could be a timing issue)".
- To do this, should I disable all items listed on the Startup tab in Msconfig? If I do this, will they be retained in the list although unchecked after the next and subsequent boots or they be lost and have to be added back in manually?
- How can I change the order in which applications start up?

Any other ideas anyone???

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Win2K Pro, V5.0.2195 Bld 2195, SP4 + all updates
AMD Athlon 1.8GHz processor with Cool'n'Quiet
Award Modular BIOS V6.00PG
ATI Radeon 9550 graphics card (128MB RAM)
System Memory 1GB RAM
Firewall ZoneAlarm Pro V7.0.337.000
Kaspersky AV V6.0.2.614
Mozilla Firefox & Thunderbird, both V2.0.0