I bought a new Sony Vaio LS 25 E computer with Vista Home Premium & 2 G of RAM. I have it plugged into my DLink DI-634M router (not using the wireless capabilities). Previously, I had a Vaio with Windows XP before and had blazing fast internet and smooth Windows Media Center operation (with 1 G of RAM).

I use Firefox and the internet is painfully slow. Not only that but Windows Media Center is choppy and going through all the menus is slow/choppy/frustrating. I have not changed my ISP provider or anything else since I got the new computer. I use Norton Antivirus but have disabled the phishing filter.

Are there fixes or tweaks I can perform on this otherwise beautiful machine to make it run better? My other applications run pretty well but since I use the internet and WMP most of the time it has been a very frustrating few days...

Could it be my drivers (even though they came preinstalled)? Is it my router? Do I need a Windows Vista compatible one?