Before installing the EndNote X2.0.1 patch, you need to lock the license.dat file or EndNote X2.0.1 may revert to being a demo.

If it reverts to being a demo, you will need to uninstall and reinstall EndNote to re-enter your product key.  To stop this from happening, do the following before you apply the update:
 
1. Open Computer (My Computer on XP)
2. Open Program Files, and then open the EndNote X2 folder.
3. Locate the License.dat file. Right click on it and choose Properties.
4. Click the "Read Only" box so there is an X here.

It is recommended that you use Program Updates.  Close all programs and turn off any background software, such as virus protection software. Open EndNote, go to the Help Menu, choose "EndNote Program Updates…" and follow the on-screen prompts.

Alternately, you can download the Windows Patch from the following URL. Once the file has completed downloading double-click the zip file to extract the MSP patch file.  To run the installer double-click the MSP file and follow the prompts.

Download the Windows patch from: http://www.endnote.com/support/ENX201_WinMac_updater.asp