i want to sort each cell alphabetically in excel

You will have to do this using a VBA macro.

For each cell in your worksheet, split the contents as individual items into an array, sort the array, then update the cell with the new data.

This function works

Public Sub SortACell(aCell As Range, sep As String)

    'Split the cell into its individual "values"
    Dim S1() As String
    S1 = Split(aCell.Value2, sep)

    'Sort the array now containing the cell contents
    'See http://www.cpearson.com/excel/SortingArrays.aspx
    Dim b As Boolean
    b = QSortInPlace(S1)

    'Rebuild the cell contents
    Dim sorted As String
    Dim s2 As Variant
    For Each s2 In S1
        sorted = sorted & s2 & sep
    Next

    'Remove last chr$(10)
    sorted = Left$(sorted, Len(sorted) - 1)

    'Update the cell with the sorted string
    aCell.Value2 = sorted
End Sub

I haven't reproduced the sorting functions here - you can find a good example at http://www.cpearson.com/excel/SortingArrays.aspx[^]
To call the code do something like this:

Range("A1").Select
Dim c As Range
For Each c In ActiveCell.CurrentRegion.Cells
    If Trim(c.Value2) <> "" Then
        SortACell c, Chr$(10)
    End If
Next

Note - I've assumed that the data in your cells contains linefeeds to separate the values (because when you paste the contents they go into separate cells) - that's the chr$(10) as the separator