How to wipe my previously synced settings, such as Desktop wallpaper, browsing history and keyboard layouts from my Live ID account?
I have tried to Delete all trusted PCs, but when i log in again, even after reinstall windows, it changes my wallpaper, windows theme, keyboard layouts and browser history again. Of course after i trust the "new" pc. I want to delete the synced data in the account itsefl, so when i trust new PC, to start from the beginning.

See if perhaps this article (http://answers.yahoo.com/question/index?qid=20071205062826AASKamo)shows the correct answer to your question.

or

1. Visit Sign In (http://mail.live.com/mail/CloseAccountConfirmation.aspx)
2. Sign in using your Windows Live ID and password.
3. Click "Close account" button.

or

This Microsoft answers (http://answers.microsoft.com/en-us/windows/forum/windows_8-security/live-id-account-windows-data-wipe/df955929-0fd1-4998-b65a-075bf4f43d97http://answers.microsoft.com/en-us/windows/forum/windows_8-security/live-id-account-windows-data-wipe/df955929-0fd1-4998-b65a-075bf4f43d97)has a possible solution.

Thank you for your answer! But closing the account isn't an option for me. I have free 25 GB in SkyDrive from before, and when i close it and make new account, it will be only 7 GB. In This Microsoft answers no one helps, i post there in the first place.

For some reason the actual MS Answers article did not link. Try this:

You can start it by turning off syncing and log in using a Local Account instead of a Microsoft Account:

1. Press Windows Key + L.
2. Click More PC Settings.
3. Scroll down to Sync your settings.
4. Drag the knob to left to turn off Sync Settings on this PC.

Once done, go online and log in to your Live account using this link (https://account.live.com/Proofs/Manage) then follow the steps below to remove your trusted pc :

1. Locate the Account Security section, and then click Manage beside Security Info.
2. Click Delete after Trusted PC.

Thank you, this is an idea (to stop syncing from local account, and then log in).
But i still looking for solution - how to wipe my saved settings from the account. How to reset the original settings? Is there no option for this?
In some moment, when i need to sync my settings and turn sync on...this will overwrite my current settings immediately.
I just want, when install Windows 8 RTM to start over with sync on and to trust my pc, not to sync my previously synced settings from developer preview and etc.