|The dsl modem may or may not be configured. Use it's web based setup to view the config if you want. One clue is the old computers IP address. If private then most likely you don't need software or need to know user and password.|
If public then you might wish to see the ISP's web page for any setup application. Most people really don't need the app but the goofy ISP's seem to force you in many cases.
"Best Practices", Event viewer, host file, perfmon, antivirus, anti-spyware, Live CD's, backups, are in my top 10