If someone is accessing remotely, then any firewall you may have should log whatever IPs connect or attempt to connect to your PC. From there, you can plug that IP into a site like WhoAmI that will tell you where that IP comes from.
How can i view who is accessing the computer, if i can view them where is the location??
You need to look in the router's interface and details of getting in there are in post 3 of this thread http://www.tomshardware.co.uk/forum/28102-18-suppoort-setupwirless. Once there, look for the MAC addresses of computers which have connected. You then need to look for the MAC addresses of all your own computers and you'll know if there are strangers in the camp.
Sadly, you can only find their identity if you can get into those other computers and check the MACs. You can, however, use the router's settings to block them from getting in again.[/#000ff]