Does this ever happened to you that firefox crashed on searching in google ?? If not then try upgrading your fully loaded firefox to latest version. few add on are having compatibility issues with new Firefox.
Firefox closing after every 5-10 min just make you switch to some other browser ?? why not try to resolve the issue ?? After Crashing submit a crash report to Mozilla. and restart Firefox and resolve issue with following simple steps :
1. Hit about:crashes in Firefox address bar. you will get a report as below
2. Click on any Crash Report, you are taken to Mozilla Crash stats. usually Details explains the issue, I suggest to check out extension tab for your add-on's compatibility.
You may Upgrade / Disable the add-on subject to the availability of the version. And you are done to use your regular Firefox.