I assume 'when i drag my photo taken' is that you used your mouse to drag the RAW file from file expolorer to Photoshop window, then it has an error message?
By right Canon 700D RAW files are supported by Adobe Camera RAW 7.4 which is supported by Photoshop CS6. Update to 7.4 version if your is an older version.
You might want to try your Canon software first see if it opens? If even Canon software can't open then maybe the original file is corrupted
If not corrupted you might want to try to convert it to DNG with the Adobe DNG convertor or use the Canon software to convert to TIFF