I am using an internet connection through Atheros AR8132 PCI-E Fast Ethernet Controller from a private party.did they can access files from my PC

I moved this from the Access forum because it does not appear you are talking about Microsoft's database program.

It sounds like you are using someone else's internet access through their network. If so, then yes, there is a possibility they can access your files.

If you are using another computers shared internet connection they can capture any packet you send to or receive from the internet. As for the files on your computer, their being able to access these files would rely on how you have your computer configured. IS sharing on? What OS do you run, some share more than they say they do. I hope I was close to the subject, some more info like OS and some info on the network would help