You really need to verify if the wireless Nic is causing the problem. You almost never see a conflict with any device and a PS/2 slot, that is quite unusual.
Try the wireless Nic in a different slot.
If that doesn't do it remove the wireless Nic and verify the mouse works without fail if it is removed.
Go into Device Manager and see what IRQ the Wireless NIC is using, what resources does it use?
I have a Sony VAIO desktop Model PCV-RX860 running Windows XP Home. I have a cable modem and D-Link
DI-524 2.4 Ghz Wireless 802.11G Router. Everything is working fine concerning the networking but for some reason the mouse now locks up. I checked the IRQ's and don't see any conflicts. The mouse is the factory VAIO 2 button w/ scroll wheel PS/2 mouse and was working fine prior to installing the wireless NIC. It had never locked up prior to installing the wireless NIC. The MB had a Wired NIC built in which I went into CMOS and disabled to try and avoid any problems. I ran out of theings to check about 20 minutes ago so I thought I'd write a note hoping I'd find someone who says "oh that's no big deal deal all you have to do is ...."
Thanks in advance, Jim D.