Glenco,
You should still have the 2.3.9 software. You haven't deleted it, just switched from it to the previous version (I assume this is 1.7.7?). You just need to 'revert' software again to get back to the 2.3.9 version.
If you go into the engineering menu (I can't remember offhand what numbers need to be pressed on V 1.7.7 to do this - its different to V2.3.9) you will see which software versions you have available.
However, without going into the Engineering menu, I think that a restore software from the Technical menu should do the trick.
As mansergh says, there's no EPG now, apart from the 'now-and-next', but its still a usable box.
Pop