I wouldn't worry about this, lil'k. You did a full scan, which is good. An htm file in temporary Internet files is not any big threat.
Feel free to delete the file you mentioned if it's still there, but it's better to let IE handle deleting temporary Internet files (click 'Tools > Internet Options', then click the Delete Files button).
PHP files are run from a web server to generate dynamic Web pages. For example, Able2Know is made up of hundreds, maybe thousands, of php files.