Have you tried to uninstall / reinstall the Linksys adapter through the Device Manager in the Computer Management console?
If you have a device which appears in the Device Manager with a yellow circle containing a question mark, its usually because the OS doesn't have or doesn't know which driver to install and apply to the device at startup. Its possible that the driver became corrupt or has malfunctioned altogether, in which case you need to reinstall the driver for the hardware to work properly again. Windows polls your system at startup for all devices present and loads the appropriate drivers from your hard drive.
IMPORTANT:: You want to make sure that you have the device driver CD-ROM available or copy the device driver to a location on your hard drive so that you can re-install it again after removing the device from your system.
I would first, uninstall the device by doing the following:
Start >> right click My Computer >> Manage
When the Computer Management console opens, click in the left hand side to open the Device Manager node. On the right hand side of the screen, right-click the device with the yellow circle, and choose Uninstall to remove the hardware device from your system. Next try to manually re-install the device by right-clicking your local machine at the top of the device tree in the right hand side of the screen, choose Scan for Hardware changes.
Windows will poll your system for any devices which are present for which there are no drivers loaded or installed. This should prompt you with the Found New Hardware wizard. You want to first try to get Windows to automatically install the hardware drivers. If that fails, then try to manually install the hardware driver from the CD-ROM or the hard drive location where you saved the driver.
Try doing the uninstall / reinstall, post feedback for additional advice.