Blank page after upgrading php and MySQL

I have only single server/hosting for my web sites. I wanted to upgrade my main shopping site from 1.3.8 to 1.5. To be safe I made a full copy of web site (zencart) into new domain name, user account, and file space on server. My plan was upgrade this second site and then upgrade the first.

Then after reading the requirements for Zencart 1.5 I learned I needed to upgrade both the PHP and MySQL on server. It is a cPanel server so last night I upgraded the MySQL to 5.5 and PHP to 5.3.13.

My problem is the main site now doesn't do anything but give a blank page.
http://weekend-racer.com

How do I go about debugging this, to get site working?
Is moving forward with 1.5 upgrade on main site, because I upgraded mYSQL and PHP, my only option now?

(And yes I did take backups first.)

Apparently you got it going.

Care to share?

Well I didn't have much choices. I figured it had to be 1.3.8 was too old for the newer software releases.
So I'm upgrading to 1.5.0 right now.

I did 1.3.9 first, but then everything looked like crap. Didn't appear right at all. Since this complained of the MySQL version I went ahead and kept installing 1.5.0.

Now trying to figure out how to fix all the layouts on site. Other than getting a logo at top the rest of it appears to have lost all configuration from the custom template.

This is what should look like.
http://web.archive.org/web/20110718023804/http://www.weekend-racer.com/

Probably have to be posting several of new threads as getting stumbling blocks. Right now I trying to diff files in template to see what I might need to change to get things looking right again.

In case anyone reads this (or my own history)
Found the problem to be fault of original person who built site. They didn't build a template directory under 'includes/languages/english/html_includes'

Created a custom template directory and then restored (from backup) all the files that had custom edits in html_includes into a html_includes/[template]

This made the main web page and rest of site appear normal again.

s58smith:

In case anyone reads this (or my own history)
Found the problem to be fault of original person who built site. They didn't build a template directory under 'includes/languages/english/html_includes'

Created a custom template directory and then restored (from backup) all the files that had custom edits in html_includes into a html_includes/[template]

This made the main web page and rest of site appear normal again.

How did you create a custom template directory?

https://www.zen-cart.com/content.php?180-how-do-i-create-a-new-custom-template
and
https://www.zen-cart.com/downloads.php?do=file&id=1393