I've had a few issues on the network here where certain PCs wouldn't let me connect remotely, or even ping! They wouldn't open GPEdit locally, etc, etc which pointed to a WMI issue.
I tried everything including the script on here but nothing seemed to work.
Eventually I found this gem of a script which takes about 10 minutes to run but has fixed every single occurrence of WMI failures I've encountered.... so thought I'd share 🙂
http://www.microsoft.com/en-us/download/details.aspx?id=7684