Sounds like you might have the wrong keyboard language installed.
Try one of the following (depending on which Windows OS you are running
under) ...
Instructions for Windows Vista:
1.Click Start and then Control Panel
2.In Control Panel, if you are in Classic View, click on Control Panel Home
(top left corner)
3.Open Clock, Language, and Region
4.Click on Regional and Language Options.
5.Click the Keyboards and Languages tab and then click Change keyboards.
6.Under Installed services, click Add.
7.In the Add Input Language dialog box, select the keyboard layout you would
like to add from the list available and click OK.
8.The keyboard layout you added will be included in the list. To set the new
layout as your default, select it from the list. Click OK to save your changes
9.You can switch between different input languages (= keyboard languages) by
clicking on the Language Bar button or by pressing the Alt + Shift keys
Instructions for Windows XP:
1.Click Start and then Control Panel
2.In Control Panel, if you are in Category View, click on Switch to Classic
View (top left corner)
3.Open Regional and Language Options.
4.Click on the Languages tab.
5.Under Text services and input languages, click on the Details button.
6.Under Installed services, click Add.
7.In the Add Input Language dialog box, choose the input language and
keyboard layout or Input Method Editor (IME) you want to add.
8.Click OK twice. You should now see a language indicator in the System Tray
(located at bottom right hand corner of the desktop by default). You can
switch between different input languages (= keyboard languages) by pressing
the Alt + Shift keys
If a language does not appear in the Input language list, the fonts for that
language might not be installed. If that is the case, follow the instructions
below.
Add language support:
1.Click Start and then Control Panel
2.In Control Panel, if you are in Category View, click on Switch to Classic
View
3.Open Regional and Language Options in Control Panel.
4.Click on the Languages tab.
5.Under Supplemental language support, select the check box beside the
applicable language collection
6.Click OK or Apply. You will prompted to insert the Windows CD-ROM or point
to a network location where the files are located. After the files are
installed, you must restart your computer.
Good luck!