Internal Server Error

I’ve been having a problem for quite some time and thought it was just at my end till some readers told me they are getting the same thing too. I’ve tried asking for help with my web host (Go Daddy)and they’re no help at this point… The last contact I had from them was that there was either a malicious code or an error in the coding of the theme or something.
Can anybody help me get to the bottom of this blasted 500 Internal Server Error problem? I’m using the current WordPress and Mantra 2.2.2 (afraid to update to the latest one as it always wipes out my header image map and other customizations and I haven’t learned how to make a child theme yet…) and my browser is Chrome. Here’s what I get and some examples of when and what I’m doing:

Always the same error:
500 Internal Server Error on the browser tab (I use Chrome) and in the page body it says “Internal Server Error The server encountered an internal error or misconfiguration and was unable to complete your request time (Ohio, US).
Please contact the server administrator and inform them of the time the error occurred, and the actions you performed just before this error.
More information about this error may be available in the server error log.
________________________________________
Apache Server at calvarycouponers.com Port 80
“

Inside Admin area:
3/29/14 11:45 PM EASTERN TIME (OHIO, US), it happened when trying to update the Google Adsense plugin
3/29/14 11:56 PM EASTERN TIME (OHIO, US), it happened when trying to publish a post
3/30/14 12:15 am EASTERN TIME (OHIO, US) it happened after clicking on”update” to correct a post
3/30/14 12:45 am EASTERN TIME (OHIO, US) it happened after clicking on publish to try to post a new post
3/30/14 12:50 AM EASTERN TIME (OHIO, US) when trying to go back to the POSTS page to choose a post to edit
3/30/14 12:53 AM EASTERN TIME (OHIO, US) after clicking on “trash” within the posts page to delete a draft I did not want any longer
3/30/14 12:55 AM EASTERN TIME (OHIO, US) after trying to move the remaining drafts on the post page to the trash

Outside Admin area:
3/30/14 12:01 am EASTERN TIME (OHIO, US) it happened after clicking on the “Home” link of my header image header map
3/30/14 12:07 am EASTERN TIME (OHIO, US) it happened when refreshing the page to see a newly published post to make sure it published ok…
3/30/14 12:11 am EASTERN TIME (OHIO, US) it happened after clicking on the post title of a post I just published so I could share it on Pinterest
I use Google Chrome as my browser and WordPress

Anyone??
Thanks in advance…
Helen B