You can capture a slowdown dump using these instructions:
viewtopic.php?f=12&t=6 That will enable the developer to determine what is causing slowdowns. If the Taskbar completely disappears and appears after a while when the Start button is clicked, that means Explorer.exe is crashing, not freezing. In that case, capture a crash dump.
Compress the dumps to a ZIP file and attach them here. Upon analyzing them, the cause of the slowdowns will be revealed and the issue can be fixed in the next release of Classic Shell.