Your processor is just too underpowered to run BOBII 2.11 on any kind of high settings, IMPO, and that is why I think you are crashing (CTD). As I have said, we are really not working on any CTD for all of our other players. I usually do not recommend BOBII for any any single core processors that are less than 3 GHz.
It might help me confirm the problem if you would post the first 20 lines of your crashlogs (the last few). The crashlog are located in your BOBII folder in a file called crashlog.txt.
You can try to reduce settings to Medium or Low, disable MultiSkin, AAA?Flak, and run small missions.Here is a Thread that may help you test and determine settings for your PC environment: viewtopic.php?f=17&t=10091
We have had some Players try to run older versions of BOBII which has helped. Here is a thread:viewtopic.php?f=10&t=26207
BOBII has moved forward since the single core processor and most of our players now run dual or quad core PCs which permits BOBII to run with MultiSkin and Max settings.