got another laptop here (on W7/64 too) that got firefox updated automatically to 3.69 without any problem
but okay, if 3.6.10 is there now
edit: but now that I'm thinking about it, this laptop with FF 3.69 was left idle with FF opened for a while earlier today, and I found it on a constant 100% CPU load...from Firefox, so may be time to upgrade again yes