Im using SONAR Home Studio 7 with an M-Audio fast track pro interface, Vista Ultimate as an OS with a dual core processor and 4 gigs of memory. I’m using mostly analogue – guitars straight into the interface – and, because of neighbor problems, I’m using plug - ins rather than amps for effects etc. I’m also using EZ Drummer. My problem is that after I record about 4 tracks – bass, drums and two guitars – I start losing quality. Either the tracks start to bleed into each other, or the drums start disappearing or the guitar tracks start losing definition. It seems to me that I’m lacking skills in separating out each track and keeping the tracks clear and well defined. I know I need to learn more about mixing and frequencies but don’t know where to go for information. Can anyone out there suggest a website, book or tutorial I can look at, or just give me a suggestion I can try myself? It’s really frustrating to get 4 great sounding tracks down and then just have them become weakened when I add more tracks. Any help is good. Eugine

Sorry, the tracks dont bleed into each other. Rather they seem to mash together.As I said, they lack separation.

Panning the tracks left and right is an easy way to expand the sound stage in a song. If they are all right in the center they can sound mashed together.
Let's say you have a song with 2 guitars, bass, drums, lead vocals and background vocals (BGV). Maybe keyboards and strings.
Pan each guitar an equal amount opposite each other. Lead vox in the middle, as well as bass guitar. Most drum synths are prepanned, so you'll hear the bass drum in the center, snare and high hat a little on the right, toms moving right to left and cymbals on each side.
Put the BGV a little to one side, your choice. Keyboards panned almost all the way to one side (unless it's the main instrument).
 
There are other things you can do to make a particular track stand out, such as equalization and compression, but my knowledge of that is limited; I usually put a compressor in the Master track, but no in-track compresion. Same with EQ; my ears are not too good, so I would probably do more harm by messing with EQ than if I didn't.
 
Post this query in the Cakewalk Techniques forum, or just read some of the great posts there on mixing and mastering. Lots of smart and talented folks willing to help there.
Good luck!
 

One easy way to get a more "disciplined" frequency structure in the mix is something like:

Put a Hi-pass filter on the guitar tracks somewhere around 150-180 Hz and pan them a little apart.

Depending on the type of sounds you're using put a different HPF on bass and kick drum at around 40-55 dB, allowing one of them go lower than the other. If the kick has a boomy reverb,  change it. Putting a little boost on the kick somewhere in the upper register of the sound (200-600 Hz) helps it to cut through.

Remember, that if all the individual instrument sounds sound "great" or "awsome" alone, they most likely are unusable together.

Your drums are not disappearing anywhere, obviously. It's just a simple fact that all instruments can't be up front.
If the riff guitar has  growling lows starting the song, you have to EQ those lows out when bass jumps in, otherwise you get a mushy porridge of lows etc. Even the left hand parts of a piano or an organ can sometimes fully sabotage the bass guitar, and need to be cut severely.

This can also be very much a monitoring question. The more experience you gain and the better monitoring circumstances you get, the better decisions you can make. What I wrote here is only a simplified  "first aid kit".

Roey Izhakis book "Mixing Audio" was a very useful book for me. It also includes a CD with sound examples. There are other recommendable ones, too, I'm sure.

Thanks for the advice. Kalle Rantaaho - What is a High-pass filter? Is it a plug-in? 57 Gregy I didnt know about the Cakewalk Techniques forum. Ill check it out.

A high-pass filter allows higher frequencies to pass through, while dimishing lower frequencies. In Kalle's example, frequencies below 180 Hz would be rolled of to give your a brighter, less muddy sound.
I believe SHS7 came with the Sonitus EQ. Check your list of effects to be sure.
If so, high-pass is one the preset options within the Sonitus EQ. Or any EQ for that matter.
If you are recording your guitar tracks mono, as you should be, they will initially pile up in the middle. That's ok. Mono tracks are very easy to pan, as Greg suggested.
Spreading your instruments across the stereo field is a big factor in getting separation.
EQ helps by giving the instruments definition.
Reverb defines the space around the instruments.
If you can get a grasp on these three basic elements, you are well on your way.
By way of example, give this a listen(preferably with headphones):


http://soundclick.com/share.cfm?id=11243952
Do you hear how each instrument has its own sonic space?
The guitar tracks were recorded mono, right up the middle. But by moving them around, and giving each a slightly different EQ, they become separate, full bodied entities.
Does that make sense?
Above all, don't get frustrated. It takes a while to learn this stuff, and we are still learning.

Stupid forum software.

Solo each track. You should only hear the instrument recorded on that track. If you're hearing instruments from other tracks, then you are routing the playback back to your soundcard when you are recording tracks. If that's the case, you have a routing issue and you have to figure out how the playback is getting re-recorded. It could be a setting that needs to be changed in your soundcard's control panel or if you're using a mixer, you're mixing the playback with the record input.