Dynamic Select Statement Using Parameterized SqlCommand Or Multiple Possible .CommandTexts

I'm trying to create an interface for filtering profiles from an SQLServer 2005 database using an html form. The form allows filtering based on a minimum level required in between one and four different columns. The first (and only mandatory) column to be filtered on has its name hard-coded into the base query. In trying to get the other three possible criteria to work, I've taken several approaches, all of which failed.
The other three potential criteria are selected from a drop down menu on the form and ideally these choices are passed into a query to be used as column names. My first attempt looked like this:
    query = "SELECT * FROM profiles_tbl WHERE (EngSkill >= @english)"    ....
    if ReqSkill1 <> "" then
                level1 = Convert.ToInt32(Request.form("minskilllvl1"))
                query = query & pickclmleft & ReqSkill1 & pickclmright1
                cmd.Parameters.Add("@ReqSkill1", SqlDBtype.text)
                cmd.Parameters("@ReqSkill1").value = ReqSkill1
                cmd.Parameters.Add("@level1", SqlDBtype.int)
                cmd.Parameters("@level1").value = level1
    end if
   above If statement was repeated for 2nd and 3rd options
Second approach was to remove all parameters from sections of the query that were appended onto the original statement. This involved lots of strings containing AND clauses with hard-coded column names which were appended on when the corresponding option was selected in the form. Code looked like this:
     query = "SELECT * FROM profiles_tbl WHERE (EngSkill >= @english)"
     ASPqry = " AND (ASPlevel >= "
    try
            con = new SqlConnection()
            con.ConnectionString = “**************string was correct****************â€?
           
            cmd = new SqlCommand()
            cmd.Parameters.Add("@english", SqlDBtype.int)
            cmd.Parameters("@english").value = english
           
           
            if ReqSkill1 <> "" then
                if ReqSkill1 = "ASPlevel" then
                    query = query + " AND (ASPlevel >= "
                    level1 = Convert.ToInt32(Request.form("minskilllvl1"))
                    if level1 = 0 then
                        query = query + "0)"
                    end if
                    if level1 = 1 then
                        query = query + "1)"
                    end if
                    if level1 = 2 then
                        query = query + "2)"
                    end if
                    if level1 = 3 then
                        query = query + "3)"
                    end if
                end if
            end if

Finally when this too failed, I created four entirely separate queries, detected how many criteria were used, and used the appropriate query, passing necessary skill level in as a parameter. I'll provide code if needed here. Queries were written as strings and then used to set the CommandText property for an SqlCommand variable.

 I think it's important to note that in all cases the most basic version of the query worked. In the first, if only the first criteria was used the statement executed fine. Same in the second. In the third, whatever query could be assigned first (even though only one could be assigned because of logical structure of if statements) worked and none of the others would. This last case was tested even with completely hard-coded queries that SQL Server 2005 validated as correct and would run.
 Any help is greatly appreciated. Will post as much code as people want/need, and if I can get any one of these methods working I'll be thrilled. I have no need for all three.
 
A.S. Moser