SLOW everything with frequent beach ball - mid-2009 MBP 3.06GHz

MBP [mid-2009 17" 3.06GHz C2D, 8GB RAM], running 10.9.1/Mavericks
has frequent beachball (beach ball) delays - painfully slow,

Office 2011 (Outlook, Word), loading Safari pages, System Preferences.

Tried disabling multiple add-ons (MOOM, Dropbox, jumpcut, Evernote) with no improvement,

tried increasing free hard drive space, no better,

no anti-viral surveillance, no crapware on board.

Permissions up-to-date, Smart Status good, Disk Utility and Drive Genius find no problems.

This was occasional with 10.8, now awful with 10.9, 10.9.1.

FWIW:

In Activity Monitor I often find multiple "Safari Web Content (Not Responding)", not sure if this is of any significance:

Thanks in advance for any ideas, suggestions!