To remove the limitations of the demo version, you have to activate GuiProf. To do it, you will need an activation code. You have to purchase GuiProf to obtain an activation code.
If you already have an activation code, go to Help → Activate.... The activation form opens:
Please enter here your name, company address and activation code.
The user name and the company name must match the activation code. The simplest way is to copy and paste them from the e-mail you received from GuiProf support team when you purchased GuiProf.