ADSL - WIFI - Remote Access DILEMAS

NETWORK:
Conexant ADSL SOHO Router 4 Port Switch. DHCP=10.0.0.3 to 6, Fixed IP of
10.0.0.2
3Com WiFi 11b & 54g Fixed IP of 10.0.0.1, Currently No DHCP, No WEP, MAC
Address selection SET to Users. ESSID not broadcasted.
PC(1) Toshiba Satellite Pro - LAN 10/100 = IP Auto, DNS Fixed PROXY set &
WiFi 54g PCMCIA (Home Only) Currently IP=10.0.0.5,DNS=10.0.0.2
PC(2) Toshiba Portege - LAN 10/100 = IP Auto, DNS Auto & Built in 11b WiFi =
IP Auto, DNS Auto.
Both XP Pro PCs belong to professionals set up on different Domains who only
want to get wireless internet access not local network.

DILEMA(1) As it is above without WEP
PC(1) can use LAN or WiFi without issue but PC(2) can only use WiFi as would
have to change LAN proxy thus messing up settings for main domain.
Currently Both PCs can ping the Router & Access Points.
Enable WEP and no DHCP provision for PC(1) or PC(2)
With MAC address limitations, No DHCP provision for PC(2) hence currently
fixed IPs
PC(2) with fixed IP's can ping routers but does not get to Internet.(Cannot
even open HTTP of routers)

DILEMA(2)
Disable MAC limitations PC(1) & PC(2) get DHCP via WiFi, Not Secure however.
PC(2) can ping routers but does not get to Internet.(Cannot even open HTTP
of routers)

DILEMA(3)
Ignore WiFi, Hardwire and set PC(2) to Auto Ip & Auto DNS, Gets DHCP.
User will keep having to reset proxy for domain ( Not Ideal )
PC(2) can ping routers but does not get to Internet .(Cannot even open HTTP
of routers)

Both have identically configured firewall for home access, disabled at work.
(TURN OFF - No difference)

Question (1)
What could it be on these PCs that stop DHCP as soon as WEP is enabled on
One or MAC limits on another.
I have set up numerous PCs using the same model ADSL/WiFi hardware on Dell
Laptops etc without these issues.

Question (2)
Where else could there be a setting in Windows XP / Policy ? Which stops
PC(2) from ever seeing the Internet.
I thaught a clue would be that it always looks for a proxy even when it is
using the WiFi which looks directly at routers IP's
Is there a conflict when a proxy is set anywhere , even not for the network
adaptor in question ?
If an alternative home profile is employed, will this bypass the proxy
conflict ?
I cannot enable a new profile without issues with /connection to the
existing domain and administrator.

This has been an ongoing headache for quite some time and I frankly can not
see where else to check !

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