My prechq register has a vendor with zero dollars owing. It prints this vendor on every printing. I think I have changed some dates somewhere but I don't now how to clear it off my chq register and out of A/P.

Does this vendor have current transactions with non-zero balances that happen to net to zero? This would be one cause for a vendor that has a total balance of zero printing on the pre-check register report. There are others, such as vendors with net credit balances.

If this is the case, you need to match up all of these transations together so that they are no longer outstanding. An easy way is to create a non-printing manual check batch entry for 0.00 and select all the transactions (both invoices and pre-payments and credit notes, etc). When posted, the Current Amount for all will be set to zero.

In recent releases of Adagio Payables, there is an option on the Pre-Check Register report to hide zero dollar amounts. Until such time that you clear up the vendor record, you can set this to hide this vendor form the report.