This week I had a problem with a Huawei 3G mobile connect card. I was not able to get it to work because it has a conflict with other hardware or its drivers. A google search brought up this interesting page explaining how to remove unused device drivers from Windows XP:

Follow these steps to view and remove these unnecessary device drivers:

1. Press [Windows]+[Break] to bring up the System Properties dialog box.
2. Select the Advanced tab and click the Environment Variables button.
3. Click the New button below the System Variables panel.
4. In the New System Variable dialog box, type devmgr_show_nonpresent_devices in the Variable Name text box and 1 in the Variable Value text box.
5. Click OK to return to the System Properties dialog box and then click OK again.
6. Select the Hardware tab and click the Device Manager button.
7. In Device Manager, go to View | Show Hidden Devices.
8. Expand the various branches in the device tree and look for the washed out icons, which indicate unused device drivers.
9. To remove an unused device driver, right-click the icon and select Uninstall.

It did not help in my case but I think this information could be useful sometimes.