Hi,
I'm currently using DB9 serial port pedals. I don't know if this applies to your situation but I don't think these would be suitable for you: I run Windows XP and I have foot pedals that plug into the DB9 serial port. Here is what I go through after having shut down my computer: On startup, I open express scribe and click settings and then controls. I activate the foot pedal setup wizard. I have settled on the COM1 Port as my choice but you should try all of the COM ports. What happens is I get a message saying that COM1 is being used. So what I finally figured out after about a week of discussion with a kind person at the TECH GUY forum, is that after trying the foot pedal setup wizard, I have to uninstall COM1, and restart the computer. Then I open express scribe again and try the setup wizard again. This usually works. I'm only telling you this so you have an idea of what might be in store if you buy these kinds of pedals.
USB pedals might be the way to go but I do not have any experience with these. But if you have a cd that comes with your pedals, install the driver first and then install your pedals as I understand that's how XP best works.
Hope this helps!