I plugged in my flash drive and nothing happened. Why is it not recognized

Since you can buy new one for $5 maybe it is time to replace it.

Same problem happens to me when I insert something into one of my computer's USB ports, such as a flash drive, it doesn't get recognized. This happens with things other than just a flash drive as well, like my iPod. I have numerous USB ports on my computer, but they all act the same. I'll insert a flash drive and even after it's not automatically recognized, I'll go into "My Computer" and it shows all the "Removable Disk" drives as being empty. I'll click on one and a prompt will come up and say, "Please insert a disk into drive F" or whatever drive I happen to click on. I've tried this with all the drives but to no avail.
http://mhelpdesk.com/field-service-management-software/

An USB flash drive is made out of a memory and extremely simple controller chip installed on a tiny board with a connector.
If the drive is completely unresponsive then the chip died. This is terminal, nothing can be done to save it or to recover what was in it.

Most probably you have a drive letter conflict? If so, right click "My computer" choose "Manage" and locate "Disk management" - here, in the middle lower panel, you should be able to find your usb-memory stick, right click it and assign it a drive letter that you're sure is not in use.

Here are a couple of articles that might solve your issue:

http://support.microsoft.com/kb/953367
http://support.microsoft.com/kb/944292

Well all good things must end and it sounds like this one has. If it doesn't connect in either computer then something inside has either been bumped loose or it's broken.

try going to "my computer" on your desktop and it should show an unkown device thats plugged into one of your drives

Go to "Control Panel>>>System>>>Device Manager.Once in Device Manager,then click on "Disk Drives" (Make sure your flash drive is plugged in before you do this).You should see your flash drive listed by it's name (SanDisk Cruzer...). If you don't see your flash drive listed, the computer is not recognizing it and your drive may have been damaged by static electricity. If your flash drive is listed, then it's a more complicated troubleshooting procedeure than I can Walk you through in one posting. So try looking in "Device Manager" and then let me know what happened.

I've seen this happen with hubs being connected to external hard drives before.

Do you have a free usb port on the back of your computer you can plug it into?

That should fix the problem.

Try system recovery if it is turned on, also you may try to unplug and plug back your drive from motherboard.

Good luck