safari freezes

( and other logged in users) keep gettting the spinnging rainbow wheel.

When you have problems with Safari in multiple user accounts, that's an indication that the startup disk needs repairing.

Launch Disk Utility located in HD > Applications > Utilities

Select the startup disk on the left then select the First Aid tab.

Click Verify Disk (not Verify Disk Permissions)

If Disk Utility reports errors, with v10.8 Mountain Lion installed, the only way to repair the startup disk is to use OS X Recovery.

The boot drive is failing, or you have some other hardware fault.

Make a "Genius" appointment at an Apple Store.

Back up all data on the internal drive(s) before you hand over your computer to anyone. If privacy is a concern, erase the data partition(s) with the option to write zeros* (do this only if you have at least two complete, independent backups, and you know how to restore to an empty drive from any of them.) Don’t erase the recovery partition, if present.

Keeping your confidential data secure during hardware repair

*An SSD doesn't need to be zeroed.