Adding PCI cards to Windows Me machine

I have an ASUS A7V running Windows Millennium and would appreciate any help:

This board has 5 PCI slots. plus Nvidia video adapter in AGP video slot.

In BIOS:
- I have PnP O/S configured as Yes
- No Serial ports activated
- Only 1 IDE channel activated
- USB activated - USB mouse connected

I have 4 cards:

SBPCI16
Dlink 510 wireless
Pinnacle Firewire
Lava PCI Parallel (LPT2)

The board manual says:
Slot 1 shares IRQ with AGP
Slot 2 shares IRQ with on board ATA100 (which is used)
Slot 3 has it's own IRQ
Slot 4/5 share another IRQ with each other and USB controller

I have tried various arrangements that Windows often says are working, but
they are not really because of the shared IRQs causing slowdowns or
malfunctions. For example, if the Dlink is in Slot 5 and I add the Lava in
slot 4, the internet connection becomes so slow it is not useable.

Right now, I have the SB card in Slot 1 and it seems happy to share with the
AGP card.

The Dlink seems to want it's own IRQ in order to work properly. It is
currently in slot 3.

The Firewire also seems to prefer it's own IRQ. I have had it sharing with
the Lava card, and Windows reports all is well, but it intermittently does
not find the AV device (Video Camera). Firewire seems to like minimum
interference from other devices. Not presently installed.

I use the Lava card to connect to a Canon FB630P scanner (parallel). It has
a pass through connector on the back, but I believe that the printer does
not work properly when connected, especially since I use it as a copier -
scan/print at same time. Lava not presently installed.

Nothing seems to want to share with the ATA100 controller but I have not
fully tested this.

Is there any chance I could get all these card working together? Prior to
the wireless network card, they did work for years with a wired NIC - not
sure why wireless makes a difference, but it does seem to!

Would Windows 2k Pro (which I have) or XP make a difference?

Are there any adapters that would allow me to connect parallel scanner to
say serial or USB or firewire ports?

Any advice welcomed!

Graham