Hi everybody, Performing a stepAIC on a glm.nb object, from a database of more than 10,000 records and about 50 independent variables, on a 64-bit workstation with two Intel Xeon 3.20Ghz processors (keeping the HyperThreading option disabled in the BIOS), using 4 out of 7Gb available RAM, and Windows XP professional 64-bit, the system always freezes and it is no longer possible to use keyboard or mouse. In spite of that, the same analysis always works on other 32-bit old computers (Pentium IV with 1Gb RAM) with Windows XP professional 32-bit, although it tooks about 10 hours. Has someone any suggestion to solve that problem? Thank you in advance, Valerio Orioli ________________________________________________ Valerio Orioli Biodiversity Conservation Unit - http://www.disat.unimib.it/Biodiversity/index.htm Department of Environmental and Landscape Sciences University of Milano-Bicocca Piazza della Scienza 1 I-20126 - Milano ITALY Phone: +39.02.6448.2918 E-mail: valerio.orioli at unimib.it