I am not exactly clear how it's happened... but suddenly I noticed that there are two identical folders on my system:

One is "My Documents" ("normal" folder located on my desktop), another is called "Mike's Documents" (located in C:\Documents and Settings\Mike\My Documents).

Both folders have identical contents. And if I change something in one of them, the same change happened in the other.

What should I do to get rid of the dublicate folder.

Here are some screenshots:

Same here, can't say I've noticed it before. Probably something to do with how windows deals with multiple user accounts. Everyone has a My Documents folder allocated to their user name. And windows differentiates by naming the accounts in your case Mike as in your login user name.

You probably don't have any other users on your pc, I don't either, but I can see the logic (window & logic oxymoron?) if there were two user accounts.

Then again I could be completely wrong.

They are not actually duplicate folders but "My Documents" is in effect a link to the login user My Documents folder. Example, if you had multiple accounts such as Mike, Tom and Harry. You would see under "Documents and Settings" Mike\My Documents Tom\My Documents and Harry\My Documents. When a user login in the system sets up the root My Documents for that user and will not see the others (without administrator privileges).

So, there is not a duplication of any data just references to the same thing. It's normal so don't need to worry about it.

Just saw that Pomthai said about the same thing.