From http://technet.microsoft.com/en-us/library/cc966377.aspx :
Microsoft Jet uses partial match (or "wildcard") characters with the Like operator that are different from those used in most SQL dialects. The asterisk (*) character matches zero or more characters and is equivalent to the percent (%) character in ANSI SQL. The other Microsoft Jet partial match characters are the question mark (?), which matches any character in a single field, and the number sign (#), which matches any digit in a single field.
The query should be modified like so:
SELECT * FROM Suppliers WHERE SupplierName LIKE 's*';