Connecting Problems

OK so with my old iPhone I had a lot of problems with connecting my iPhone. It would connect and disconnect, and it would take a lot of work for it to finally work. Just upgraded to my 3G this morning and am now experiencing the same problems when trying to sync. Now my hardrive is a pretty old one because I got it from my aunt's work so we would just have a computer to keep all my music on since I have so much. I keep getting a message when I connect that my phone could run faster in a 2.0 USB. Could this be the problem. If so does anyone know if you can buy a 2.0 USB that I could install or if I will just have to switch over to the new computer. Thanks