Hello Mary, welcome to the TiVo Community.
It might be helpful to know Which model of TiVo DVR that you are using? WeaKnees.comŽ Find Your TiVo Model
No need to do the "C
verything" (format?) the worst case is that you would re-do the "Guided Setup". (Takes a long time but keeps your recordings, season passes and wish lists)
Does "have lost all program information" mean you have lost the Guide data or just the "To Do" list?
1: If it is the guide data go into "System Information" -> "Settings" -> "Network" and force a connection to TiVo.
2: If it is the "To Do list" change the order of a Season Pass this will force a data re-sort.
IAC if the 2 steps above does not help a re-boot may be all you need.
All this is assuming that the DVR has an active subscription with TiVo.
FYI: I noticed my old Series 2 does not have any upcoming recording because all the shows on analog cable that I have season passes for are on season break.