Hello
Let start by first stating u will never get the 54mbps the service states. This is only a theoretical speed. I assume this is a wireless card?
OK, now lets start troubleshooting.
First: let start by doing a check disk. If u have a Win XP disk use the Recovery Console check disk. This is the preferred way. If not use u can right click the C:\ >tools>check disk select both options,follow instruction. This will give us some what clean file system.
Second: If u can not use your laptop download the drivers from the manufacture website and save them to a flash drive. U might have to use a friend PC. Uninstall the existing drivers first, then reinstall the new drivers.
Keep in mind that location make a big difference in receiving the signal. Write back and let us know the out come.