excel generates low resousce message

Everytime that I open excel I get the message that my system is dangerously low on resources. My system locks up and I must reboot. I am running Windows 98 with all the latest updates and I have scanned for virus possibilities with Norton. I haveuninstalled & reinstalled excel to no avail. I have 128mb of ram and tried to run with 90% mem available. Has anyone seen this before.