Hi everyone, If you've been following the other thread on "Rgraphviz, R 2.7.0 and Windows XP", there's been quite a few trials on how to get the Windows binary of Rgraphviz corrected installed and working properly on R 2.7.0. I thought I had it all figured out with my - SOLVED! post, but then Sebastien Gerega found that using some function from topGO caused R to crash because of the problems with Rgraphviz. Thanks to the help of quite a few people, the following steps SHOULD get Rgraphviz installed and working on Windows (except for one minor hiccup, noted at the end): 1. Close down any R sessions you have open. 2. Download and install Microsoft Visual C++ 2005 SP1 Redistributable Package: http://www.microsoft.com/downloads/details.aspx?familyid=200B2FD9 -AE1A-4A14-984D-389C36F85647&displaylang=en 2. Download and install the Graphviz 2.16.1 from the archives: http://www.graphviz.org/pub/graphviz/ARCHIVE/graphviz-2.16.1.exe . This link should automatically download the correct file, but if you're doing it manually, you have to get it from the ARCHIVE, not the Windows download page, which only has 2.18 and 2.16.1.static. 3. Check your PATH to see how Graphviz was added: Start Menu -> Control Panel -> System -> Advanced -> Environment Variables. In the box labeled "System variables" scroll down to "Path" and then click on Edit. Something like "C:\Program Files\Graphviz2.16\Bin"; should be at the very end. IF IT HAS QUOTES AROUND IT, DELETE THE QUOTES (leave the semicolon). Then click OK several times to get out of the System menu. 4. Now open R and download and install Rgraphviz using: > source("http://bioconductor.org/biocLite.R") > biocLite("Rgraphviz") (if you've already downloaded Rgraphviz with these commands before doing steps 1-3 above, you do not have to do it again) 5. Try loading Rgraphviz: > library(Rgraphviz) Hiccup: on my machine when I load Rgraphviz, I get a Windows error box that pops up saying: Point Not Found. "The procedure entry point g_intern_static_string could not be located in the dynamic link library libglib-2.0-0.dll". However, if I click OK, Rgraphviz continues to load fine and appears to work fine. I'm not sure what to do about this last little problem, other than it seems to be ignorable. I hope this works for everyone!! Jenny Jenny Drnevich, Ph.D. Functional Genomics Bioinformatics Specialist W.M. Keck Center for Comparative and Functional Genomics Roy J. Carver Biotechnology Center University of Illinois, Urbana-Champaign 330 ERML 1201 W. Gregory Dr. Urbana, IL 61801 USA ph: 217-244-7355 fax: 217-265-5066 e-mail: drnevich at illinois.edu