How do I write special characters without AltGr key?

The simple answer is to use Ctrl + Alt instead of Alt Gr. That works for all special characters on my keyboard.

I would imagine that the keyboard layouts you're referring to (that doesn't have an Alt Gr key) simply only have two versions of input characters on each key, i.e. the normal character, and the one produced when holding Shift.

Here's a general way. Not the fastest, but for any character regardless of keyboard layout:

• Click the Start button (or Windows key).
• Type: "Character Map" without the quotes.
• Enter.
• Select the character you want.
• Click Select.
• Paste it wherever you want.