Hi Sherri,
Yeah, I'd agree that having to prefix the decimal number with a zero each time can be annoying. Except that I can't duplicate this, so there is something else happening. I haven't seen this before.
Does the same problem exist when typing in other amount or unit fields? It might point towards something set up in Windows that doesn't like leaving the zero untyped, though this really doesn't make sense. That it's a new computer means that not everything will have the same setup as before (in the Windows sense).
I tried looking at the Windows regional settings options on an XP workstation, and I didn't see anything helpful there.