Maybe it's an hardware problem. Do you have 3D games ? Do they run well on your computer ..?
What is your configuration ? CPU ? RAM ? Video card ?
Could you send me the System.Log which is in your TE2005 directory ..?
To do so, give me your email using this form:
Then I'll send back an email to you, so you'll have my email address where you could send this file.
(I don't publicly give my email address to avoid spam)