[dialer] qhsnXX

I've a problem with a dialer.
I don't know how, but a malware creates a file in Windows\Temp directory. This file's name is "qhsnXX.exe", where XX is a number that automatically changes itself. After the windows session is started, suddenly at any time, the "qhsnXX.exe" file is loaded in memory and it works like [or it IS] a dialer: it disconnects my current connection and tries to make a new connection [a phone call to the usual very expensive telephone number].
Well.
Spybot can't solve the problem, neither my antivirus software can.
I obviously denied internet access to the file qhsnXX.exe [using Spybot]. However it can still make the phone call. My antidialer software is useless and doesn't stop the dialer.
I delete the qhsnXX.exe file, but it re-creates itself with a different name, so it becomes a useless operation [i.e. if I delete qhsn08.exe, in short time the malware creates qhsn09.exe, loads it in memory and makes the phone call].
If I could add qhsnXX.exe file to the black list in Tea-Timer, probably I would solve the problem for a bit of time. But, as I already wrote, the dialer/malware creates a copy of itself with a different numeration, and I can't do anything to stop its activity.

Is there a solution to my problem?
Thanks for the attention.

epd