If you can not connect Samsung Galaxy S2 with your PC cause of it can not detect the phone, there is a USB driver for it.
First of all you have to wait until you've connected your Samsung Galaxy S2 via USB data cable to your PC with the USB debugging mode
If this option is not done correctly,follow the following instructions.
Go Settings - Applications - Development - USB debugging - Hook purely
to find it. After you change this setting on your Samsung Galaxy S2, please connect via USB data cable to your PC and the required drivers (which were already made by the manufacturer intigriert on your mobile) should then automatically install on your PC.
If you still have errors please look under USB connection times (above the taskbar of your screen) and put your cell phone once portal tools.
Because I guess the only shop on your phone or memory card access and it is therefore not working.
Most of the users who just recently bought this great android phone Sam¬sung Galaxy S2 I9100 struggling an issue when tried to con¬nect the phone to the PC to access the SD card though, and somehow it didn’t really work. An error message appears "Android MTP Failed!".
Here are the some tips below might help you to the task and man¬aged to access the phone’s inter-nal SD card on PC. Just ensure that you have already installed necessary drivers for your Samsung Galaxy S2 or install KIES on your PC.
-Enable usb debugging from Menu > Settings > Applications
-return to home screen
-plug usb cable in
-pull down status bar
-press ‘ connect usb storage’ button
or try this method:
Alternatively, without USB debugging enabled
Go to Settings > Wireless & Network > USB utilities and click the button > then (and ONLY then) plug in USB cable.
You can find drivers and firmware here: Samsung galaxy s2 usb driver