samad64:
you need to winmerge the template files. The google checkout module overwrites a file that the paypal express module uses, and that is a template file.
A few people have already winmerged them, one of which is chainman. Check the Google Checkout thread to see if you can find some better instructions
From http://www.zen-cart.com/forum/showthread.php?t=47318&page=47 :
I've found that , if you want to use PayPal Express checkout too, you will have to do a bit of merging the GoogleCheckout code into the new versions of the 3 template files found in includes\templates\YOUR_TEMPLATE\templates. All of the 1.3.7 versions of those files have PayPal Express modifications in them. I found it easier to modify tpl_login_default.php and tpl_shopping_cart_default.php from the new versions by adding the GCO code. With the tpl_checkout_payment_default.php it was easier to add the PayPal Express code as it was better documented.
From http://www.zen-cart.com/forum/showthread.php?t=47318&page=49 :
It is probably easiest to use winmerge to compare the two files. But I don't have that tool, so did it the hard way.
Essentially, it's probably easiest to start with the new 1.3.7 version as your base code. Search the comparable GCO version for "google". In two of the files, there are only a couple of lines in the GCO version. Copy and paste these lines into the 1.3.7 version. (I'm hedging about which files as I don't have them in front of me.)
In the third file, there is a lot more "google" in the GCO code, and it is well commented. I used this at a base and compared the 1.3.7 version, picking out the PayPal Express sections and copying and pasting them into the CGO version.
I think either way would be about the same.
I placed all merged versions of the template files in the YOUR_TEMPLATE/templates folder, as specified in the Google Checkout mod. This will keep your mods in override mode and keep your 1.3.7 default template code intact.
