What is the best wmv video editor?

In Lucario's defense, you asked for "the best wmv video editor". Unfortunately, the best programs cost money (After Effects, Sony Vegas etc.). You could use Windows Movie Maker, if you have a computer running Windows XP. You could also use Windows Live Movie Maker, which is on Windows Vista and Windows 7. These two are free. They are pretty good for being free, and since you seem to have problems with Windows Live Movie Maker, you could uninstall it and then install the latest version. Also, theoretically, WMM and WLMM should be the best, as WMVs were also developed by Microsoft, like WMM and WLMM.