Assuming you're using windows, you need to set up the Windows IME to type in Korean. It's not just an odd font (And even if it were, it will only show correctly for those with the font also installed, and that's unlikely for the reader it would just appear as random letters).
First: Do you have east asian languages and literature installed? (안녕하세요 - Can you read that, or is it simply squares? If you can read it, the language files are installed, if not you will need your windows installation disk to install the language files).
Okay, this will differ a bit depending on whether you're using XP or Vista, but not too much so you can probably fill in the blanks. My laptop has Vista (sadly) so I'll be describing as that.
Open your control panel (Start -> Control Panel). Find "Regional and Language settings." Open that. Hit the 'Keyboards and Languages' tab (At the bottom you'll see a text regarding installing other languages, incase you don't already have Korean language files installed).
On the 'Keyboards and Languages' tab, hit the 'Change Keyboards' button. A new window should open. Here you should see a list of installed languages and keyboard settings (Right now, it probably only lists English.) Click the 'Add' button. Another window should open with a list of languages. Find Korean on the list. Open the Korean options, keyboard options and select 'Windows IME.' Click OK.
You should now see Korean as well as English in the window box. Now you can switch between Korean and English keyboard settings. If you don't see the language bar, you may need to go to that tab and tinker with it to get it towards your liking.