Best I can suggest is:
IF(ISERR(SEARCH(find_text,within_text,start_num)),"not found","Found")
Find_text is the text you want to find. You can use the wildcard characters, question mark (?) and asterisk (*), in find_text. A question mark matches any single character; an asterisk matches any sequence of characters. If you want to find an actual question mark or asterisk, type a tilde (~) before the character.
Gavin