I don't know how to use my USB 2.0 Flash Drive!  

Did it come with an installation CD?
What version of Windows are you using?
Maybe it did work - check "My Computer" for an extra drive.
Also make sure your USB Port is functioning properly.

Most likely, you are missing a driver.

After you plug it in you have to shut down your computer and turn it back on again. The computer should recognize it as a new piece of equipment and tell you what you need to do. Probably nothing else. That should do it. It will show up in your 'My Computer" section as an additional drive.

its weird try to restart your pc or otherwise your system does not support it

you just check for your usb drivers. if drivers are not installed then only your computer will not detect your pen drive. You will find usb drivers in your computer's mother board cd.

if you are using the xp series of microsoft, most USB flash drive driver are included on the said operating system so, the system should appear a small usb icon on the task bar near the system clock,,, and before you can use it,wait for the confirmation coming the operating system that your hardware has been successfully installed, after this you can now save files to your thumb drive..

I have no idea, either

Welcome to myLot, sidley86! :)

The only thing that I can think of is that you have a 2.0 device and 1.0 slot. You should check the user manual that came with your computer, or even the invoice that was packaged with it, that is, if you still have it, to help determine which it is. On the bright side, if you do have a mismatch, you can purchase a 1.0 to 2.0 converter from a place like Best Buy. Good luck!