When changing a file encoding, your first step should always be a backup. You can mess things up quite easily.
The encoding of the future (i.e. future standard) is utf8, thats why all modern editors have it as its standard. So, you might consider to convert your files from latin-1 to utf-8.
Nevertheless, after backing up the files, the following workflow should work.
Open your tex-file in a normal texteditor (e.g. notepad), open texmaker/texstudio, set the default encoding to the one you prefer, create a new document and copy/paste the contents out of notepad. Don't forget to save the new file.
You should also be able to recode your documents from within texstudio/texmaker, you can try it, you backed up your files.
If you prefer to work with a command line, you can have a look at
iconv:
Code: Select all
$ iconv -f utf-8 -t iso-8859-1 <yourInFile> -o <yourOutFile>
Batch convert latin-1 files to utf-8 using iconv
The smart way: Calm down and take a deep breath, read posts and provided links attentively, try to understand and ask if necessary.