For those who don't like to install any software on their PC, online converters are better choices for you. Here, some reliable online ASF MP3 converters are listed for you.
Specific guide on converting ASF to MP3 online (take Zamzar as an example):
Step 1: Visit https://www.zamzar.com/convert/asf-to-mp3/ and then click "Choose Files…" to select ASF files from your PC.
Step 2: Once the uploading process is finished, click the Convert button to convert ASF file to MP3.
Step 3: After a while, when it informs you that File Conversion Complete, you can click the Download button to save the converted MP3 files to your PC.
Tips. Almost all online converters have maximum upload limits, so it's not recommended to convert large files with them. Meanwhile, if you meet with unexpected conversion error, long conversion time or something like that, resubmit the files to fix the problem. And you can never be too careful about those pop-up ads and other misleading information on those websites.