low memory

i am facing a strange problem.when i open exel it works some time after that it ocurs low resources and dagerosly terminate application.
Action Taken(systems configuration PIII 1,0b ghz,64 mb ram,20gb hard disk)
1 increase ram 64 to 128 mb
2 uninstall office 2000 proff reinstall office 2000 proff.
Pl suggest me right solution