Have you recently changed anti-virus programs, or uninstalled the one you had? Word hooks to them to scan documents, including templates, before trusting them. If an anti-virus was installed or uninstalled incorrectly, Word might hang because of mis-communication with it.
Try this:
1. Open Word to create a new document.
2. If this works, change the macro security settings, this way:
In versions of Word prior to Word 2007:
1. Click the Tools->Options menu item.
2. Click the Security Tab.
3. Click the Macro Security button.
4. I suspect the Low radio button will be set. Set it to High.
5. Click OK.
In Word 2007, 2010:
1. In Word 2007, click the round Office button in the upper-left corner of the window. In Word 2010, click the File tab on the Ribbon.
2. In Word 2007, click the Word Options button. In Word 2010, click Options.
3. Click Trust Center.
4. Click the Trust Center Settings button.
5. I expect the "Enable all macros" radio button will be selected. This relies on an anti-virus to check macros. If it's set, click the Disable all macros with notification radio button instead.
6. Click OK.
If that gets you past the Antivirus scan, I suggest you figure out why it was hung up in the first place. Until you do, you should be able to work with Word, at least.
Good luck.