Hi i have loaded a midi file onto a midi track it show playback in the track but im hearing nothing????

First thing to check is that the output is assigned to an instrument to play the track.
 
Here's a video on MIDI for beginners that explains the concepts and set up in a (hopefully) easy to understand way.

thanx for that i seem to be having trouble assigning each midi track after iv dragged a midi file with multiple tracks on it ...its only giving me drum map manager on outputs

See if this might help you:
 

I cannot hear MIDI playback

In order to hear MIDI playback you will always need to route the MIDI tracks to some MIDI device. Whether it is a synth built into Windows (MS GS Wavetable Synth), software synth (DXi VSTi) included with Cakewalk, or an external hardware synth, there are a few steps to take...
Internal Sound Card Playback: If you have a built-in sound card and want Cakewalk to play MIDI through the synth built into Windows, you will need to switch Cakewalk's driver mode so it can see it.

1. Go to Edit > Preferences > Audio - Playback and Recording (Options > Audio > Advanced in legacy products)
2. Change the Driver Mode to "MME (32-bit)" and click Apply (in legacy products put a check in the box that says "Always Use MME Interface" then click OK)
3. Restart the program and let the Wave Profiler Test your hardware.
4. Go to Edit > Preferences > MIDI - Devices (Options > MIDI Devices in legacy products). You should now see "Microsoft GS Wavetable S/W synth" under outputs.
5. Select this new device and click [Apply (if available) then OK.

Software Synth (DXi, VSTi) Setup: If your sound card or audio interface supports WDM or ASIO drivers, you should use a DXi or VSTi virtual instrument as your synth, rather than the Microsoft GS Wavetable synth, which will not be available in these driver modes:

1. Go to Insert > Soft Synth and add one of the synths from the list (click the + sign in the upper left).
2. Make sure you check "MIDI Source", "First Synth Audio Output" and "Synth Property Page" from the Synth Options window that pops up. Once that particular synth is in view, press F1 for specific documentation on that synth (if available).
3. Cakewalk should automatically create and route the necessary tracks for your soft synth. You can now route existing MIDI tracks to this soft synth by changing the 'Output' setting in the MIDI track to the synth you inserted. Note - For detailed instructions, see the tutorial called "Using Soft Synths" or "Playing and recording software instruments" under Help | Help Topics. These tutorials will be very helpful to you.

 
 
https://www.cakewalk.com/Support/Knowledge-Base/2007013179/I-cannot-hear-MIDI-playback

Mesh, good post.

Have you some synthetic loaded to play the midi track thru?
open the browser (shortcut B) and click the tab synth
if you see an empty blank box, click on the plus and add a synth, use first output setting and SIT
then assign your midi tracks to your synths

Since those Cake midi instructions are from 2011, I'm not 100% convinced about the instructions on #2:
 
2. Change the Driver Mode to "MME (32-bit)" and click Apply (in legacy products put a check in the box that says "Always Use MME Interface" then click OK)
 
Since (I'm assuming:)) most of us, if not all use ASIO x64bit.........I'd probably skip that step.

If you are only seeing drum maps you don't have any MIDI devices selected in Prefs-->MIDI--->Devices. If you don't have any external MIDI devices to assign then you need to insert a softsynth such as TTS-1 or Dim Pro into the project.
 
They will then show up as output choices in the MIDI output dropdown. Having said that you'll get an option to insert a MIDI track and audio output or a Simple Instrument Track at the time you insert the synth. The outputs will be automatically assigned in that case.
 
Having said that I demo doing it manually in the video so that the concept of MIDI tracks and the required assignments is more obvious (hopefully).