First thing is to simplify your challenge. Do you have an antenna attached? Are you using the MMCX adapter connection for the antenna, Adapter cables for Orinoco cards are different and won't work.
Can you configure the 350 card via ACU? if so, does its encyrption settings/security match the AP. Can you connect to any other APs via the 350 card? Go to a WiFi hotspot and test your system and card there to see if you can attach to a Linksys or other off-brand AP?
Make sure you know the wireless security settings on the AP and match them on your wireless adapter cards. Can you connect with the access point wirelessly with any other wireless cards? If yes, can you connect the 350 to the AP using the Win XP wireless settings and not the ACU? One tip is to make sure the security settings on both card and AP are turned off, make the connection, then tighten security and encyrption back down.
2. Use device manager to confirm that the computer sees the Cisco card, then delete the card from device manager and remove the card from the computer.
3. Uninstall Cisco ACU and re-install the latest ACU version you can download; ACU ver 6.5 is one of the latest versions.
4. Now plug the 350 card into the computer and see if the computer loads and configures the card.
5. If it doesn't, try the other Cisco card.....if neither card loads and can be selected as the primary wireless network connection, the cards may both be bad. Let someone else test the cards with a computer that functions with Cisco 350 cards to make sure the cards are not broken.