internet connection sharing problem?

[Nick]

I used to use my lap top as a connector to get online from my xbox via the PC connected to the wireless network at the house. This worked for years. Recently, it has stopped working. Now when I go under properties of my wireless network and check the allow others to connect to the internet to get internet access (which is what used to work), it tells me "An Error Occured while internet connection sharing was being enabled"

Bridging the local with wireless does not work either. Any suggestions on how to fix internet connection sharing?

HP Laptop
Windows Vista
64 bit