Someone has registered my sisters company domain

[A D]

I disagree with the opinions above on this. If your sister has a common law trademark, she might have recourse. You can win a UDRP or an ACPA based on a common law mark. If her company name is distinctive and protectable, there certainly is something she can do about it.

I agree, contact Zak and he will send them a letter, she has a definite chance of winning becuase she has used the name as her business for a period of time.
You do not need to have a trademark to prove you have created an identity and it is easy to show it was registered in bad faith.

contact a lawyer, a letter to this person should do the trick.

-=DCG=-