There's something installed that integrates with Explorer (most likely for right-click context menus) that is holding things up. Can you think of any program that you've installed that performs anything like this?
One way at possibly figuring it out is using Process Explorer
. Open it and then attempt to do anything that will display the symptoms. When it's hung up on it, observe which process is taking up the most CPU (if it's not already sorted by CPU or CSwitch Delta column, do so). I would assume it'd be Explorer.exe. Either way, click on the process and it'll bring up a window display current running threads. Again, discover which one is taking up the most CPU/CSwitch Delta and then double click that. Click the "Copy All" and paste here for reference. Do the same for a number of the various actions that are hanging on you, and describe what you did for each one that caused it to hang.
You can also generate minidumps or full dumps to provide for us to analyze. While it's hanging, right click the suspect process and go to Create Dump
then select the dump file size you want. Full dumps are large and you'll need to zip up and upload to a 3rd-party filesharing site, but they offer excellent details on what's going on. Minidumps may also be able to assist, but it's preferred to have a number of them.