Office XP-Excel2002 W/SP2

I got system with P3-50Mhz/320MB System Memory,Un-nstalled the Office97 and had configure Office XP with Both Service Packs,Now When I am accessing one of several Excel files,which were created/copied in Office97,those files on opening up start processing of their own by indicating in status bar as “calculating cells : 0%” and taking very long time to process,i think approx few hours to calculate and freezing the system for other apps.,hence wanted to know if any one can tell me some alternative to skip this.

Thanks