I helped a client recently with some issues using WordPress. His issues were:
1. The WYSIWYG menu bar is not there to post messages in IE8 (it is there in Firefox, so its not the end of the world)
2. I can’t add tags to posts
3. I can’t drag widgets to the side bars
I installed a copy of the latest WordPress into a spare folder on my machine and did some comparisons and then after drilling down to most of the relevant folders I uploaded the files and folders that were missing. I did a few checks in the admin panel and watched WordPress restore itself to full functionality.
The lesson here is be sure you’ve uploaded all the WordPress files with your FTP client – check for any errors in your FTP client log file after uploading and before closing the client.