A google search for ADSLTEST.exe returns many hits, perhaps there is something there that rings a bell. Since you don’t give the location that it is in there is no way to try and associate it with a program and see if it might just be legit for testing an adsl line.

You could also check the offending/suspect file at: VirusTotal - Multi engine on-line virus scanner
Or Jotti - Multi engine on-line virus scanner if any other scanners here detect them it is less likely to be a false positive. You can’t do this with the file in quarantine, you will need to move it out.

Your IP address is usually dynamic changing each time you connect to the internet, this can be true if that connection is by dial-up or ADSL. It is possible to request a Static IP address some ISPs offer this, but you usually pay a premium for it. Check your ISP’s support pages or FAQ and see what it says about static and dynamic IP addresses.