Joining PC with OS windows 7 using AD user account

why is it like whenever i join a PC running windows 7 using the user's AD account, is prohibited instead of using our Domain's username and password?

From serverfault macoy

• Are you using a domain user account and not being succesful, or are you trying to use a PC's local account to join it to the domain?

  In the first case, there could be some policy in place which only lets some users (probably domain admins) join machines to the domain.

  In the second case, you're doing it wrong (TM): in order to join a domain, you need to authenticate against it, so you'll need to use a domain account (and possibly an administrative one).

  From Massimo

• I do not understand what is asked. What is exactly the difference between "user's AD account" vs. "Domain's username and password"?

  This is the basic principle of domain administration that machine can be joined to domain by domain administrators nut not by AD "common" user accounts

  MarkM : -1: In a default AD installation, regular users *are* allowed to join 10 computers to AD. Also, Account Operators and any other group with the appropriately delegated permissions can also join or remove as many computer accounts as they want. Not just domain admins.

  vgv8 : I searched this webpage for "default" string and there was no occurences. It was not even answer, it was question since I had no comments available at that time

  Kara Marfia : You posted as an answer. Expect what you say to be treated as such. Otherwise add a comment, or ask a new question.

  vgv8 : @Kara Marfia, had you read another, upvoted answer? What's the difference in it with my answer? It also has question. I was sure that I could answer and wanted to hear clarifications

  vgv8 : What I cannot understand is that your "community" "activists" insert off-topic comments and then accuse me in being off-topic. For ex., what is the point in your constant off-topic comments? Just to accuse me in this?
  From vgv8