This is not a hardware issue (unless you consider not having the "fastest of the fast" as a hardware issue). By default the mintMenu also looks for packages to install, and there just happen to be a lot of packages with the letters "pul" in it. So the CPU is shortly locked in a loop going through that list. It does really depend on your hardware. Searching for "pul" only locks up mine for 3 seconds or so.
You can either: right-click Menu, click Preferences, go to Applications tab and remove checkmark on "Search for packages to install". Or follow the link by wayne128 for a small edit you can do to the Python code to fix this (direct link: http://forums.linuxmint.com/viewtopic.php?f=165&t=61489#p384373