I don't think Wifi will allow direct connection from PC to Phone at all.
Not from PC anyhow.
I know that Windows 7 isn't smart(or featured) enough to allow this type of browsing over Wifi.
Some better software is needed.

If you have the phone connected to your Wifi network, try MyPhoneExplorer, it allows you to specifically connect to the phone using it's established IP address if need be, but you don't usually need to do it this way.
It's phone searching ability is quite good, and it should connect to it very quickly.
Or, try ES File Explorer on the phone and connect to the PC from the phone.

Also, what version of Android is the phone running? This may be important at some point.