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That processor speed and amount of RAM will probably work, but it won't be blazing fast, and you may want to go with a light weight desktop environment (in other words, *not* KDE or Gnome which are resource-intensive) It's a harder call on the USB 2.0 card, but again it probably would be OK.
Rather than to spend money on the card though, I'd suggest using a Live CD such as Knoppix, which you can download from LinuxISO
. A Live CD is basically a fully functional "Linux system on a CD", and all you need to do to get up and running under Linux is to burn the CD, put it into the drive, then reboot (make sure your BIOS sequence looks at the CD first) Knoppix has excellent hardware detection capabilities, and may be able to get those existing USB ports working. Good luck with it -- J.W.