Just for your information, this is the last e-mail that I have recieved from Spyware Doctor:
Thank you for contacting PC Tools.The Rivarts.A detection in most cases is picking up the following registry
entry as Rivarts.A.
HKLM\SYSTEM\Currentcontrolset\Services\mchInjDrv
This appears to be a false positive detection.
MchInjDrv is a third-party driver used by many security applications to provide process protection. However, this driver can also be used for malicious purposes by those intent on writing Spyware. There are some AntiSpyware programs that do not understand that this is a legitimate driver that can be used maliciously but in most cases is used legitimately.
Spyware Doctor in fact uses mchInjDrv as do many other legitimate security programs.
Thank you to everyone for your help.