Text File Problem (Searched but couldn't find)

I have looked back over past threads but can't seem to find a solution to my problem.

I understand how to write into text files and how to read out of them, my problem is being able to amend a particular line.

Is there a way to pull out a line change it and put it back into the same line.

i.e.

In text file have

Line1
Line2
Line3
Line4

I want to be able to change maybe line2 to Fred so that the text file after the changes would read

Line1
Fred
Line3
Line4

I hope you understand what it is that I am trying to do.

Cheers for any help
Steve

Read the entire file into a string array.
Change one of the strings and write them back to the file.
I answered a simular question earlier, the difference is that that guy wanted to delete one line.
If you read the post I'm sure you can figure it out.

Best regards

Thanks Joacim,
Steve