Thanks Jim for your help. I was able too get past the frustration I was experiencing with Quicken 2019, even though I still have problems.
I am unable to remove the erroneous 143 shares in the placeholder AT&T Inc. dated 1/16/1990, displayed in Investing overview. The correct placeholder information should read 288 shares @ $12.50 each with a cost basis of $3600.00. I tried using the "Enter Transactions" window to correct this entry, to no avail.
The Investment Transactions displays the correct information for AT&T Inc. which includes 288 shares @ $12.50 each with a cost basis of $3600.00.
What else might I try to fix this? Below, I have included screenshots of my two Window displays. I hope this may help.