I started having MySQL errors with my 1.6 installation while adding products to the cart system so I decided to try an upgrade to magento 1.7. I attempted to perform the upgrade through the admin area and it got hung up while updating the files. Now all I get is a 500 internal server error when trying to either view the site or access the admin area. I tried replacing the database with a copy I had backed up prior to the site meltdown and it still didn\\\\\\\\\\\\\\\’t help. Does anyone have any ideas of how I can try to salvage this site? Thanks in advance for any help!!
if you have a backup maybe you should delete it all and try to import/migrate a copy to a fresh installation. Not really sure that it is a good advice but it seems to be a solution. You can move data with help of cart2cart http://www.shopping-cart-migration.com at least you will avoid problems with upgrading.
Just follow the steps and remember to back up both your database and server files before starting any kind of server maintenance. The 500 server error should be able to be setting the correct file permissions after upgrading via Magento connect.