Ironic77

Had the same problem just now on SP1 with latest fixes.

This helped:

I looked in services.msc and discovered that the Windows Search service was in a "stopping" state. That is, it appeared to be hung in that state. The same would apply if you see the process stuck at 25% (quad core) or 50% (dual core) or 100% (single core).

I opened Task Manager, found the SearchIndexer.exe process and killed it (you'll need to show processes from all users, requiring administrator privledges). Then, I restarted the "Windows Search" service (I may be crazy, but I like search when it's working normally).

Upon doing so, my machine started behaving normally again -- I can rename files without explorer.exe hanging. The search service is also working normally and the performance has improved.

Hope this helps.