Firefox with MS Security Essentials.
Only using the NoScript extension, but the computer still randomly hangs up to half an hour with a variety of errors (mostly "gre" or "chrome"). Upgraded and searched for a fix but no joy. Everyone says start in safe mode and see if that fixes it.
A few examples:
Script: resource://gre/modules/XPCOMUtils.jsm:325
Script: http ://s.ytimg.com/yt/jsbin/www-core-vflnHl_P9.
js:51
Script: chrome://browser/content/tabbrowser.xml:370
Script: chrome://bprivacy/content/bprivacy.
js:684 10.14
Script: chrome://global/content/bindings/textbox.xml:55
Script: chrome://mozapps/content/downloads/downloads.
js:1155