You can have absolutley no background programs running. Turn off your screensaver as well.
In the compatibility mode, under properties I checked the last two settings.
Display --> Disable visual themes
Input Settings--> Turn off advanced text services for this program.
You need to Change your Computer settings and increase your paging files if the game is running slowly or crashes are apparent.
Also I found it ran without a crash or glitch if you increase your paging file, and reset your Performance Options. (Right Click on My Computer-->Properties-->Advanced)
Mine are set to the following:
Visual Effects: Adjust for best Performance
Advanced: Processor Scheduling--> Programs
Memory Usage--> Programs
Virtual Memory (this is your Paging File)
minimum = 768MB
maximum = 1536MB
I've also chosen to turn off System Restore while playing these games. But that is just my preference.
As far as Jack the Ripper itself.. in the Game options I would recommend having this setting:
uncheck: Shadows and antialiasing
Check or uncheck
(I've found these make little or no difference)
uncheck lock cursor
(I have my setting just to the left of medium