Of course, the bleedin' obvious with windoze, when in doubt do a re-install
. If you haven't used it for a long time perhaps some other program caused a minor conflict? Whatever, you fixed it.
There's a thread on here about TuneECU. Basically, someone reverse engineered Tuneboy and released it for free. It doesn't read Tuneboy files, they have to be converted to .hex files. TuneECU has some additional features that Tuneboy doesn't have, it also has a couple I don't like - the graphs are displayed in a garish, multi-colour format (which I hate!) and the "3D graphic display" is useless, imo, whereas Tuneboy's is really nice for fine-tuning a map. It also works with the Tuneboy cable, so it won't cost you anything to try it.
As for a suitable tune, quite a few have had good success with the Arrow race tune. You can get it from the Tuneboy site, best thing is to try it. Towersk has also posted a slightly tweaked tune which also has had good reports.