You've downloaded a theme, but when you try to open the .sis file, nothing happens or you get an error. The Solution: The most common cause is a "Certificate error." Because these themes aren't digitally signed by a verified publisher, your phone may block them by default. Follow the steps in the installation guide (Step 3) to change the software installation settings to "All" and turn off the online certificate check. This is a well-documented fix for this exact issue.
This Chinese platform, which translates to "Theme Love," was founded in 2009 and is an excellent resource for Nokia C7 themes. It offers free downloads for a huge range of devices, from N-series and E-series to C-series phones, including the C7. The site supports Symbian S60 V5 files, which are the correct format for your C7, and offers direct downloads for your phone or via PC. nokia c7 themes free