How to compute the inverse of a matrix with some complex elements
 

Using Office 2003, how can I compute the inverse of a (4x4) matrix with some
complex valued elements? Specifically, matrix A is formed from the
eigenvectors of a different matrix and has some complex congugates. If
A=(aij), for i,j= 1,...,4: then a11, a12, a21, a22, a31, a32, a41, a42 are
all real, while a13,...,a44 are complex with: ai3 and ai4 as congugates.
This means that if A is partitioned into its real and imaginary components,
A=C+iD, then both C and D will be singular