Let us assume that there is a matrix in R and you would like to remove both the 
columns and rows with NA values in it. Following is the code 

1) Create a matrix with 4 columns and the values are from 1 to 16  

x = matrix(seq(16), ncol = 4) 
 

2) Now change the value in 2nd row, 3rd column as NA. 
x[2,3]= NA 
 

3) Now print the matrix  
> x
     [,1] [,2] [,3] [,4]
[1,]    1    5    9   13
[2,]    2    6   NA   14
[3,]    3    7   11   15
[4,]    4    8   12   16

4)To remove rows and columns with NA:
> x[complete.cases(x),complete.cases(t(x))]

     [,1] [,2] [,3]
[1,]    1    5   13
[2,]    3    7   15
[3,]    4    8   16