You seem to be experiencing either hardware and/or System problems.
If you don't feel competent to sort those out yourself, take your Mac to an Apple Store and have them look at it.
Kernel Panics are not something to be taken lightly and are usually a sign of memory, Hard Drive or something else failing.
I've temporarily solved the problem by using a troubleshooting account i created last year. Using that account i was able to update the software in the regular fashion using the Mac App Store. Would this still indicate that something is about to fail? When i tried updating my laptop (numerous times) the Mac crashed and rebooted at the same point in the installation process each time, which might point to a problem with my user acciount, or something incompatible. I had this same problem when trying to update other software using the Mac App Store a couple of weeks ago: each time i tried to update software i would be prompted to enter my Apple ID and password, and once entered, i'd get a message saying "An unknow error occurred." This happened repeatedly for 3 weeks. To get around this, i used my "Troubleshooting" user account to update software using the Mac App Store, which worked perfectly. For some strange reason, that problem disappeared last week, and now it's resurfaced again while trying to update iWork yesterday. So a similar problem, yet the same workaround. Anyone have any thoughts? No Apple store anywhere near where i live so it's not possible to book a genius appointment, and Apple's on-line help is useless...i went many rounds with them a few weeks on the phone and wasted much time. Anyway, thanks to anyone who might be able to offer a suggestion or fix. The workaround certainly works, but is indeed inconvenient.
If this were my computer, I would back files up to a separate drive then wipe this drive clean and reinstall the OS. Start over fresh. By the way, it feels great.
Something less to do is just use the new account.
Is the "troubleshooting" account a regular admin account?
I would suggest that you create another admin user account. Manually move your files over and set up the new admin account (if you have iCloud set up, then a lot of the settings will automatically get set for you once you turn it on in the new account).
Stop launching into the old account. You could keep it around in case you forgot something in the new user account. I'm not sure, but you may even be able to just delete the old account when you are sure you don't need it anymore. Best of luck.