Disconnect Periodically

I've had this problem for awhile on my HP Pavilion a1450n. Vista Ultimate 64
bit. Periodically, usually 1 to 1 1/2 days, my DSL connection will
disconnect out of the blue. I have a wireless connection to a Netgear router
and a Embarq modem. They are fine because another computer is connected when
the HP disconnects. That tells me it's the HP or Vista, not the router or
the modem. This didn't happen with XP so I'm assuming it's Vista.

Today I was uploading some files to my website and in the middle of it,
disconnect. I went to the other computer, opened IE7 (Vista 32 bit) and was
able to browse fine. I can do 'a diagnose & repair' and anything else I'm
prompted to do but I can't connect. I also have a LAN card, same thing with
it.

Now, once I restart the computer, all is fine. For about 1 - 1 1/2 days.
Nothing will work to get me connected but a restart of my computer. This has
been going on for a month or two, maybe more. Anyone have any idea what's
going? Thanks