For anyone who posts here to have any chance of helping you we really a lot more information from you, sorry!
Which exact version of Samplitude do you have, and is it actually Samplitude Pro?
What are your computer specs? Please read this post to see the level of detail needed. Ideally, add all that information to your signature. (If you click the blue Signature link at the end of this post you will see my setup, as an example.)
Following on from number 2, what soundcard/audio interface are you using (internal or external) and which audio driver type (MME, ASIO etc.)?
With that level of information we may well be able to offer some useful advice to you.