Ok in know this sound silly but have seen it before are you sure your installing the correct driver for the card?  Another thing to try would be to boot into safe mode and try installing the driver there.
Hello All: I can't connect to the internet via integrated wireless card. I put a fresh copy of XP Pro on a formatted Dell D600. Everything works fine except for the network controller. The drivers seemed to install fine but It Displays an exclamation mark in the device manager. Only LAN shows in the network connections. I have uninstalled it and reinstalled it, in both regular and safe mode but same problem. I tested the wireless card in another unit and it worked (Broadcom. Bcm94306MPSG) so it's not the card. I updated the drivers using the Dell drivers and I tried the Broadcom drivers from their site as well. I also updated the BIOS and made sure wireless was enabled within the BIOS and Fn+F2. I checked for IRQ conflicts, I also reinstalled the OS again. I can connect to the internet via rj45 Ethernet but nothing seems to correct my integrated wireless card problem.   
network controller error "device cannot start code 10" (Dell D600 xp Pro)