Is there ways to know unauthorized access to your pc?

[villageidiotY2K]

Hi folks, im newbie to pc.

i was transffering data from my desktop pc to iphone by making my desktop pc open a shared file.

from my iphone, i connect to the shared folder via ipV4 on the folder menu, and its logged in as a owner, so i think needs a username and a pw to even connect to my shared file.

 

But i only shared a single folder on my desktop with owner only being able to access. ("Everyone is not selected)

I noticed I could gain access to all the files in my desktop via "Users" folder.

For one to access via "Users" folder, one must know the user id and password right? (same username & pw for login onto the desktop)

 

but when I unclick "share this folder" that i was sharing on my desktop, msg pops up saying 2 users will be disconnected from this folder,

im the only one who uses my user id & pw

anyone know any cases why this is happening?

i live in a condo, and all other neighbours use the same ISP as its fixed in this condo.

**same ISP, but not shared meaning each tenant needs to be subscribed directely to the isp

i've recently change my router password from default 

 

any info be swell