Newb,
first of all the full formula, in case you forgot something:

=IF(ISNA(VLOOKUP(A4, INDIRECT("'" & K1 & " information'!$A$4:$L$97"),
12, FALSE)),"No Client Info For This Year",VLOOKUP(A4, INDIRECT("'" &
K1 & " information'!$A$4:$L$97"), 12, FALSE))

Second, I just tested a variant, just in case and it works. Please
check Tools|Options the Calculation tab, to see if somehow calculation
was set to Manual. If so, you would get the new values by pressing the
function key F9.

Finally, replace K1 in BOTH places in the formula with whatever cell
you chose in your Comparison sheet.

Write back if neither of these works.

Kostis Vezerides