upload media button not working

Ok after updating to 3.5 I’ve had issues uploading images. Looking through the forum and the suggested “fixes” so far I’ve tried:

– deactivating plugins. In fact I’ve deleted ALL my plugins and the issue still didn’t resolve itself.

– cleared browser cache, also tried in various browsers and on different machines (PC and laptop have the same issue)

– switching templates, same issue remains in any template. And yes I tried the suggested twenty twelve template. Doesn’t fix the issue.

– tried re-installing WP 3.5, nothing

– tried re-installing WP 3.5 manually (via FTP) – nothing

never had ANY issues before the upgrade to WP 3.5