Keyboard error went using MS Exel

Keyboard problem on MS Exel
Hi.. every one i have a unique problem in one of my user system. She is using Dell D630 Notebook. What happen is went she open file on MS Exel, her keyboard setup will change automaticly i.e. when ever she press ( key it appear * but if key-in on other application there is no problems (i.e MS Word, Notepad or MS Outlook) FYI..all the MS Office is MS Office 2003. After restart the NB she was able to key-in as normal, went she open few files on MS Exel the problem start back…
Please advice me.. thanking in advance 🙂