When i try editing my document it says modifaction is not allowed as selection locked

The document has been saved as read only or is locked to source that cannot be opened. Save a new copy using "Save as" with a new name and you should be able to edit it.

I know it's a problem with the "Full Version" but please verify that you are not using a trial version of the software. This typically happens when the trial edition has been left unactivated therefore it goes into a reduced functionally mode.
Other than that, the document you're trying to open may be marked as final or is protected.
Here's a helpful link. http://www.404techsupport.com/2009/01/13/microsoft-word-this-modification-is-not-allowed-because-the-selection-is-locked/

I hope this helps.

This usually means that the document is protected. If you click on the Review tab you should see Protect Document on the far right hand side of the screen. When you click on that, you should see Restrict Formatting and Editing in the drop down. Click on that and on the right hand side of your screen you will see options. If you see "This document is protected from unintentional editing", your document has been locked. Click the Stop Protection button at the bottom of the sidebar. If it doesn't ask you for a password, you should be all set. If it asks you for a password, then the person who sent it to you doesn't want you to edit the text on the page.
If that's not what you see, let us know. Hope this helps!

Microsoft Office 2007?
If yes, your trial has finished. Now you need to purchase it.

It sounds like you're in a Protected doc. Go to Tools>Protection & see if there is a command in the submenu that reads as "Unprotect Document". If you attempt to remove the protection you may be prompted for a password. If this isn't the issue be sure to specify version info when you respond.
If using 2007, go to the Review Tab of the Ribbon if the Restrict Editing & Formatting Task Pane isn't displayed. Then click the Protect Document icon (right end of the Ribbon) & choose Restrict Editing & Formatting. At the bottom of the pane click the Stop Protection button - if there is no password require you will be allowed to revise the document.

If this only happens in one particular document, try opening that document and clicking on Tools | Unprotect Document.

If all new and existing documents are locked for editing, then it's probably because you have not activated your Word/Office software, or because you have an expired trial version of Office. What happens if you start Word and click on Help | Activate Product? If you are already activated, a dialog box saying so will appear. If you are not activated, the Activation Wizard will start. If you have an expired trial version, a dialog box will prompt you to enter a valid product key or purchase a key online.

Please let me know if this has been helpful or if there is anything else I can do. Thank you.

If using 2007, go to the Review Tab of the Ribbon if the Restrict Editing & Formatting Task Pane isn't displayed.
Then click the Protect Document icon (right end of the Ribbon) & choose Restrict Editing & Formatting.
At the bottom of the pane click the Stop Protection button - if there is no password require you will be allowed to revise the document.
If prompted for a password & you don't know what it is you can't make changes anywhere the Find Next Region... And Show All Regions... Buttons highlight for you

By the way, your Office is activated?

Here is the unlock key fro MS office 2007.
KGFVY-7733B-8WCK9-KTG64-BC7D8

hello sir i have an problem in Microsoft office 2007 when i type any word the the msg comes "the modification is not allowed the selection is locked" how can i solved this problem plz give me any solution

This is an error that happens when you try to modify or use a document that is locked.
1. Open the document
2. Select the Devloper tab
3. Click on "Protect Document"
4. On the Restrict Formatting and Editing Task Pane on the right side of your screen, Click on "Stop Protection" on the bottom of the task pane
5. If there is no password, you can start using the document