It's not your computer, Firefox tends to "crash" when you have many addons.
I can tell you that I have a quad core and my FF still takes a long time to open (sure it could be the HDD, but in this case it isnt).
Until FF changes its core in order to be able to initialize better I shouldn't use it for regular browsing, chrome wins there.
As for hack bar, glad to see an addon that still works for updated versions, unlike many of others.