i want to have a way to track the pay back from an original price for
a stock by deducting the dividends i receive for that stock example i
started with a purchase of $2,000.00 for pepsi and i had 5 different
dividends of say $10.00 so now the orginal invested amount has become
$1950.00 and the next dividend i enter will reduce that amount again. 
is ther something out there like this which deals with lowering an
initial dollar amount by each dividend received and coul have as many
as 50 rows with different original amounts and on column the ability
to enter the dividend that atumatically lowers the original amount
paid?

The "original invested amount" never changes.  The dividends are
equivalent to interest.  If you deposit $10,000 in a bank and the bank
pays 5% interest do you subtract the $500 per year interest from the
$10,000?  No.