ArcMap crashes when running any tool always Spatial Analyst

Discussion created by jm.garcia001 on Jun 20, 2011
Working with ArcMap 9.3.1, arcinfo license. I've been working smoothly with spatial analyst tools, but this morning to execute a process (Zonal Statistics as table) ArcMap has crashed and now every time I try to run a spatial analyst tool crashes.
Could you help me?