On a P4 Model 521 neither /noexecute=OptIn nor /noexecute=OptOut with colinux excepted, set via Performance Options GUI as suggested by the two links below, worked to avoid blue screen. Only putting /noexecute=AlwaysOff in the boot.ini file allowed me to start colinux. I'd much prefer OptOut so if there's a fix please let me know.
 
The P4 521 is included in this list: http://www.intel.com/products/processor_number/index_sitelet_view2.htm
Intel's Processor Identification Utility can be found here: http://support.intel.com/support/processors/tools/piu/sb/CS-014921.htm
 
Kevin
 
 
Aaron Miller wrote:
 > George P Boutwell wrote:
 >
 >> 2) It could be DEP, an change in SP2 enabled DEP where before it was
 >> disabled.  Check the Mailing List, it's got dozens of e-mails where
 >> this was the problem and several work-arounds (the main one being to
 >> modify boot.ini and set /NoExecute=AlwaysOff), but since most of those
 >> we have found an dialog screen that allows you to add coLinux to an
 >> 'exception' list and leave your boot.ini alone.
 >
 > Off topic, but I'd love to know where is this dialog screen of which you
 > speak; I've never seen anything like that, but I've also only been
 > running XP for about two months.
 
 the list George spoked:
 http://home.arcor.de/henryn/coLinux-DEP/DEP-options-and-boot-ini.png
 
 it is a long clicking way to this menu:
 http://home.arcor.de/henryn/coLinux-DEP/DEP-programs-BIG.png
 
 --
 Henry Nestler