1.Have any USB or external drives worked on your computer?
2.What is the make and model of your computer?
3.What happens when you connect flash drive?
4.Have you received any error message?
5.Have you tried by connecting the same flash drive with the different computer?
As all the hardware devices have drivers associated similarly USB devices also have it. Sometimes proper drivers do not get detected after the initial installation so reinstallation of the drivers helps resolve the issues.
You may check after uninstalling and reinstalling the USB drivers if you are able to connect. You may disconnect all USB devices and then perform the following steps:
A.Click Start, and then click
B.Click System and Maintenance, click
System, and then click Device Manager.
Note If Control Panel is in Classic View, double-click System, and then click
Device Manager. If you are prompted for an administrator password or for a confirmation, type the password, or click Allow.
C.In Device Manager, double click to expand "Universal Serial Bus controllers", right click on the Host Controller, click "Uninstall" and click "OK". Check if at all there is an exclamation mark along the driver, it suggests issues with the driver installed.
D.Repeat the step 2 to uninstall all items under "Universal Serial Bus controllers".
E.Then, restart your computer and Windows 7 will reinstall all USB controllers automatically.