Matt,
Most of these problems are usually attributed to the fact that you are actually running other applications at the same time, and unfortunately, it often has to do with other Adobe applications, or even an antivirus. The only way around this is good planning 😉
Aanarav should be credited for bringing a cool little software to our attention called EndItAll, it will kill all the processes running in the background BEFORE you start Premiere. I can almost guarantee you that most of these issues will go away. If they don’t, you need a clean OS or Premiere install.
For the firewire device issue, make sure that only one device is plugged in, and that should be the one Premiere is using. After Effects is also the one you have to look out for since it also uses firewire out for preview.
BTW, HP is well known for bundling a bunch of crap that usually runs at start up. I would also uninstall anything that says HP in front of it, unless you know you absolutely need it.
Good luck,
Vince