PTSnoop that RE-installs itself repeatedly during reboot IS a back door virus. But also, the correct driver for PTSnoop dated 4/23/98 for the PCTel modem IS necessary for the modem to work correctly.
Here's what to do to get rid of the back door virus. And I found that it does NOT need to be ref'ed in Win.ini to behave like the virus.
Go on-line and download a file called pctel56k.zip (if you can't find it let me know), unzip and install it to a MODEM folder on your hard drive.
Remove the modem from 'Device manager' then shutdown and remove the board from the machine. After reboot, remove the HSP modem software from 'Add/Remove' software. Now (or earlier) go into MSConfig and Regedit and remove or deactivate any PTSnoop.exe refs.
Reboot. Check all is well, PTSnoop.exe should NOT show up in MSConfig this time. Shutdown, then reinstall the modem hardware.
During boot choose 'Skip File' everytime Win98 tries to install a PCTel or HSP modem file.
After reboot, your machine will have a non-working PCTel or HSP56 modem installed.
Go to 'Device Manager' and 'Update Driver' for the modem to install the drivers from the Modem directory you created. Now go to control panel and click on 'Modem - Diagnostics - More Info' to test it. It should find it. If not, you are on your own.
Done.