problem opening Microsoft Office & Excel

I have recently installed Microsoft Office 2000 on a XP machine and I can open Outlook, Access & Powerpoint but I am not able to open Word or Excel? I am running 800 x 600, 32 bit mode and when I open these applications I change to 8 bit mode. I have installed all service packs and updates from Microsoft and this hasn’t fixed the problem. I have installed and re-installed, ran Dell Diagnostic tools and no fixes…can someone help??