Is there an equivalent of lspci under Windows or a free download. A quick google didn't show anything obvious

Rus

This will sort of show what hardware you have, even for shared IRQ PCI stuff.

right click my computer, select Manage. Drill down System Information, Hardware Resources, IRQs.

This works for 2000, it should be about the same for newer versions.

try wcpuid from http://hp.vector.co.jp/authors/VA002374/src/download.html
it can show some pci info