Hey there, and welcome to crystalXP.net ! 
I'm going to help you, so .. first of all go to:
1- Start > Control Panel
2- Open Add/Remove Programs.
3- Search for the crystalxp brickopack and delete it.
4- Restart your Pc.
5- If you still have a classic windows theme/visual style:
6- Right click on your desktop.
7- Go to Properties > Themes
8- Choose Windows XP.
9- Go to Appearance.
10- Choose Windows XP Style.
11- Click on OK.
There you have it. 
Let me know if you have further problems.
Sincerely,
[C]radle.eXe