Subdirectory posts giving 404 Error. Need Help.

Hi All,

I am having 2 WP installs, one is the root & other a subdirectory. I am not a techie hence preferred new WP install over WP Multisite. My root WP has been running good but the subdirectory i installed today is having a problem. Link to my root is HERE & link to subdirectory HERE.

Subdirectory all posts are showing 404 error , however all posts are shown on the subdirectory homepage. I am really confused about this.
I searched a lot & found few tricks like adding ErrorDocument 404 /index.php?error=404 to .htaccess but without any success.

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Now i need help on how to solve this issue. Is there any other file which needs to be tweaked ?

Would really appreciate if anyone can help me out on this.

Thanks