'The dependency service or group failed to start' Help, please.

Hi. I'm a newbie here, so please bear with me. My Dell XPS M1330 on Vista Home Edition was working fine until one day it said that it'd found an 'unknown device', followed by several unsuccessful attempts to install that unknown hardware. After that, my computer just cannot connect to the internet at all, even though it can detect wireless signal. I tried the LAN wired connection and the result was also the same. There is no problem with my router as it works with other computers. As far as I know all the drivers are up to date. I even tried to uninstall my latest Window updates, thinking that they might be the cause, but still it made no difference.

I was wondering if anyone has any suggestions what to do. How do I find out whether this is a hardware or a software problem?

My Network Adapters are:

Intel (R) Wireless WiFi Link 4965AGN (Ethernet 802.3)

Broadcom NetLink Fast Ethernet 802.3 (657nd60x)

Please help. Thank you so much in advance.