ISP what can do

Solution
Theoretically yes, any system that is network-connected to your PC can interface with it.
Practically, that would be hard to do if you have the appropriate measures in place, have not installed software that allows remote access, have a firewall in place etc. Also, a properly configured system should give you a warning when a remote desktop application is running.
Finally, if the ISP would try to do that, there would be more than one PC affected, impossible for them to pull such a scheme for long without being discovered. Needless to say, that would be the end for them.
Theoretically yes, any system that is network-connected to your PC can interface with it.
Practically, that would be hard to do if you have the appropriate measures in place, have not installed software that allows remote access, have a firewall in place etc. Also, a properly configured system should give you a warning when a remote desktop application is running.
Finally, if the ISP would try to do that, there would be more than one PC affected, impossible for them to pull such a scheme for long without being discovered. Needless to say, that would be the end for them.
 
Solution
At any one time you will probably have a dozen instances of svchost.exe running in Task manager. They all have something to do with the Internet connection but to find out which each one does is a bit tortuous. Why do you think your ISP is spying on you?