That nagging screen will be your companion until:
1. You buy a license or insist your seller meets his bargain.
2. Ongea na watu wana volume licenses, most co and gov have them. Ask nicely.
3. If you are so hard assed are unwilling to do the above, go open source. Tafuta Ubuntu desktop. No one will ever both you again. And the you will be free like Kigui