Internet Problems - AMD 64 bit

Hi,

I just bought an HP AMD Turion X2-TL60 Dual Core 4GB 250HD 64 bit laptop.
At first I couldn't connect to the internet, then connection was intermitent. I have a Vonage Modem connected to the ComCast Modem. I did not have problems connecting with my old computer XP SP2.

ComCast couldn't figure it out. Said it was HP Problem and connected me to HP rep who said 64 bit was having problems with ComCast modem, and would have problems with all my 32 bit programs including Adobe CS3.

Is this true? Has anyone had this problem or problems with their software working on 64 bit computers? If yes, then I might as well bring the computer back. If HP rep was not truthful, I'd like to know, too.

Thanks in advance.