It's possible with conditional formatting (in cells B4:B30 in the attached):
Code:
=AND(ISNUMBER(SEARCH($C$2,B4)),ISNUMBER(MATCH(ROW(B4),ROW(INDIRECT($A$2 & ":" & $B$2)),0)))
The formula used is in column I but this is not needed - it was only for development of the CF formula.
Is vba a must?