Linksys WMP54G crashing system

Hi all
Anyone with any ideas on this one.
Just got the WAG54G-UK all in one box and it's gone in fine. However, when
I installed the WMP54G PCI wireless adapter on my PC upstairs with Win XP
SP1 installed on it - it didn't want to play ball and locked up the PC. On
a reboot it started to load windows then suddenly went back to the
POST,tried to reboot itself (unsuccesfully) - and generally kept
misbehaving.
I took it out and everything booted up fine again. I changed the PCI slot
but got the same thing.
It's the second one I've put in thinking the 1st one was faulty after
spending a couple of hours on the phone to Linksys support.
The bios for the mobo (an AOpen AX63Pro) is 3 yrs old ...possible cause of
problem and 2, the PSU is only 250W for a PIII 700 512mb RAM, CDRW, DVD Rom
2 HDD's and 1 ISA sound card.Though it's been running fine before without
just the adapter.
The first card would actually install, but refused to detect the router and
it's network but that also acted weird .... sometimes not being seen by
windows on a reboot.....
Maybe a different make of wireless PCI adapter might be worth a go .... I
doubt it though!
Any suggestions?
TIA
Phil

The answer turned out to be in the linksys hardware - don't buy the
wireless PCI card!!
I looked a little deeper into the card and found out it was a bummer..
I'm usually a research freak on hardware but on this occasion I was in the
local PC world store with my gift vouchers in hand.
I knew the linksys WAG54G was looking favourite for my dosh for the router
so thought I'd go for narrowing down the compatibility probs by buying the
same make wireless adapter ....wrong move!!
After all my probs I then looked a bit further and found that 80% of people
had a nightmare installing this card - there's no pattern with OS's or
hardware at all, you're either on of the few lucky ones and it'll go in no
probs, or one of the majority that have a nightmare.... I was one of the
majority |:0(
I found out after just a short while, that the D-Link, Netgear or Belkin
54g cards work like a charm with the WAG54G and after returning yet again
to PC World, exchanged it for a D-Link.
I put it in, half expecting the PC to throw another wobbler but lo and
behold, not a sausage this time, in it went flawlessly and picked up the
Linksys router without a hitch and now I'm surfing the net on my other PC
like a good 'un.
Moral of the story?
Do ya research before parting with your hard-earned ... it'll save ya some
grief...take it from me!!
Over and out.