If your keyboard and mouse hangs after a cold reboot, this might help:
Enter your machine’s BIOS / PnP-PCI setup and change IRQ12 to „Legacy by ISA only.“ (This option may appear differently, depending on your specific BIOS).
The problem is caused by the fact that the PS/2 port (where your mouse/keyboard are connected) may not like sharing PnP IRQs. If your PnP BIOS decides to add another card to IRQ12, the port may hang.

Jonathan Hall (jonathanhall@compuserve.com) adds:
I have had the frozen mouse problem and have found a work around for it. The mouse is a Logitech wheel mouse on PS/2, and the pointer would freeze at boot. I fixed it by telling BeOS that it was a two-button mouse.

tom costin (tomcostin@mindspring.com) adds:
If neither of these work, go into your bios and change „Assign IRQ to VGA to yes“. Worked for me…
[Editor’s note: These bugs should be cleared up in a future release]