I don't use P2P file sharers because of both the copyright issues and the risk of finding malware spread across my system.
So I can't help specifically. It seems that your Frostwire is set to load at startup. Any good and reputable software will have a Tools > Options, where the user can search through for options like, "Load at startup", or similar, and de-select that. So, open Frostwire and look for it's options.
Some thing to note;
1] File sharing software will generally seek to open your computer's folders so that your files can be accessed and shared by others.
2] They don't mind if this is done in the background, ie, without your knowledge. So you startup your computer, the P2P software loads at startup and begins sharing your files without you needing to do anything.
3] Some 'less than reputable' software will make it difficult to prevent it from being loaded at startup. Real Player products spring to mind. There are several options in Real Player to stop 'Load at startup', but none work. We often have to use the Windows "System Configuration Editor" to de-select items in the Startup tab. To access your System Configuration Editor, go to Start > Run, type in msconfig and click OK. Goto the Startup tab and look for any entry that refers to Frostwire. De-select it.
Mark