VBA to find eigenvectors

hi,
So far ive got the matrix to do it for a 3x3 matrix but i need to change the coding so it works for a 4x4.
Ive got a method to genereate a random matrix, find the eigenvalues by bisection. Now i need to find a method to find the eigenvector of that eigenvalue via codig. I have enclosed the spreadsheet.

Thanks