If the computer isn't set up correctly you'll end up with spelling errors in your work. The problem is even if your own computer is set up correctly and you later continue the work on your own computer, the language for the work done on another computer persists.
The document I read had many errors which was a direct result of the language set up on the university's computer.
To check the language settings when using Microsoft Word, type in the words colour and color. The word color should be highlighted as being an incorrect spelling. Many academics also consider the ize spelling variations to be American spelling and will mark accordingly. The ize spelling is an accepted secondary spelling in Australia, but if you wish to only use the preferred primary spelling, you'll need to obtain the Exclude file I produce for Microsoft Office, which marks over 2,000 secondary spelling variations as incorrect. Using the Exclude file leads to a more professional document with consistent spelling. There is nothing wrong is using either the ise or the ize spelling variations in Australia, but to use both in the one document is considered incorrect.
Whilst it isn't wrong to use the ize spelling variation in Australia, if your work is read by others, keep in mind many other people consider the ize spelling variation to be an incorrect spelling variation. Whilst they aren't right, if you're applying for job and the potential employer thinks you can't spell, it won't help you and may even reduce your chances of getting that dream position.