Here we provide some tips for you to tackle the problem.
How to Contect Samsung Galaxy to PC
Preparation: Before connecting to computer, uncheck "USB debugging". (You can go to "Settings" > "Applications" > "Application settings" > "Development" > "USB debugging")
1. Go to "Settings" and choose "Wireless and networks".
2. Select "USB utilities" and tap on "Connect storage to PC" (when your phone is not connected to PC). Then, it will pop up a window telling you to connect USB cable to use mass storage. Do not click "Cancel" now.
3. Connect your phone to PC with a USB cable, and press "Connect USB storage" on your phone when it reminds USB is connected.
Notes: For different versions of windows, some computer cannot recognize your phone or find the driver. Download and install Kies on your computer in this situation. You need not open the software, and just follow the steps talked above. If it still doesn't work, you're suggested to connect your phone to another computer.
You can download Kies here: http://www.samsung.com/cn/support/usefulsoftware/KIES/JSP
Still cannot connect your phone? Exclude the situations one by one as follows:
1. Check if Windows Media Player has been installed on your computer and update it to the latest version. Be sure the version is 11 or above.
2. Disconnect your phone and open Samsung Kies. Click "Connection failure settlement" and try connecting again.
3. Replace the computer USB port or use the backward USB port of desktop.
4. Turn off the anti-virus software or firewall on the computer.
5. Try with another computer if it results from the software compatibility.
Hopefully these tips can be helpful for you when connecting your Samsung Galaxy to computer.