Internet problems with dv6375us

[ambidextrous]

Hi people, I am a newbie, and I just bought a new HP Pavilion dv6375us Entertainment notebook which came with Windows Vista Home Premium. Everything was fine, and the Internet was working blazing fast - it is an Ethernet LAN connection that my apartment provides.
I don't know what I did wrong, the only thing I did was try to install SuSE Linux on the machine along with Vista - a dual boot. But ever since, my Internet Explorer refuses to open any web pages. I talked to HP Tech Support guys and they said an OEM and another OS won't work together, so I ended up restoring the notebook to factory settings - still to no avail.
Another thing I had done was to use the wonderful partitioning manager Vista comes with to create many drives and some free space on the hard disk. The Linux was then installed on the free space. After restoring the system I deleted that partition, but nothing seems to happen.
This very connection, this very Ethernet cable works just fine with my old laptop - as I keep switching the cable between the laptops hoping in vain that it will work again on the HP!
Any help will be deeply appreciated.
The IPv4 and IPv6 addresses are assigned very well, and there doesn't seem to be any problem with the drivers or Vista itself.
Well, so I restored the system, but the Internet was still not working. So I shut the notebook down for a couple hours, and then when I restarted it, the Internet started working! The Norton Security that came with the notebook installed some updates, prompted me to restart the machine, and the connection was gone again. This is what has been happening lately - it comes and goes, while the connection stays stable on my old laptop (the same connection).
It crossed my mind that perhaps the Norton firewall and Windows firewall are conflicting each other, so I uninstalled Norton, but the Internet isn't up yet... do you by any chance have any experience with a similar situation?