Frozen Prusa Mid-print (1 reply)

I am having huge issues with my printer freezing mid print.. Often, it will freeze towards the beginning of the print and all movements are locked unless I unplug the printer from my computer for a few second. The hot end also retains the heat while frozen. It is almost like it just locks up. I have also successfully printed 3 hour prints before and other times I can not complete 2 minutes worth of printing! Here is my set up and what I have tried so far..

-Prusa
-printrboard
-pronterface
-slic3r
-115200 baud rate
-Macbook pro with os x 10.8.4
-run with computer power plugged in
-set sleep for hard disk and computer to never

and here is what I have tried..

-ferrite chokes on usb cord
-changing baud rate to 250000
and other suggestions I have seen online..

Please let me know any suggestions that you have as I want to get my printer running!
I do not have access to a sd card but I might have to purchase one in order to solve this problem..

Thanks,
Clayton