Hi!
Here's the situation: When i have some audio loaded on one track (ex. drum) and i want to record a new track while playing back the drumtrk, i will always hear the drumtrack on the guitartrack (so when i solo the guitar track, the drum track is also recorded on the guitartrack). 
It's very subtle, but stil audible, and of course completly unwanted because i want to layer several guitartracks.

Is anyone having the same issue? I think it has something to do with the onboard soundcard of my laptop, but i have no idea how to get rid of that problem. 
Thanks a lot!

http://forum.cakewalk.com/tm.aspx?m=1370491

Go to my website for recording help, soundcard and equipment recommendations.
http://www.beaglesound.com/
http://soundcloud.com/beaglesound/sets/featured-songs-1
i5 2500K, 16G DDR3, Win7x64, Asus P8P67, MOTU Ultralite Hybrid MK3
Privia PX-3, Yamaha MO6

I've already tried those steps, the settings in windows are al good, but still no change...

I hate to tell but the problem might be the realtek itself.  the realtek is just a chip on the motherboard and is not the best thing for recording software.  (or the drivers for the realtek)

you might could try ASIO4ALL to see if that improves your performance in sonar and change to ASIO driver mode.  but that's just a "band-aid"

a true recording soundcard with recording soundcard drivers would be best.  check my website for some recommendations.

Go to my website for recording help, soundcard and equipment recommendations.
http://www.beaglesound.com/
http://soundcloud.com/beaglesound/sets/featured-songs-1
i5 2500K, 16G DDR3, Win7x64, Asus P8P67, MOTU Ultralite Hybrid MK3
Privia PX-3, Yamaha MO6

Trying to have a  good working on board realtek sound card with a professional program like Sonar is asking for lots of trouble and frustration.

Realtek hardware is not made to run a professional DAW.

If I were you, I would look into getting a real sound production sound card or interface-

If you want good low latency performance, make sure you check for that and be careful what you buy. Dont go USB for low latency performance unless you select about 3 units out there that are good fro this- Roland quad or Octacapture, M-Audio fast track ULTRA, or RME babyface or something from RME-

Lance

Lance

http://dipdive.com/member/LanceJonesMusic
Gigabyte Micro ATX Motherboard   
i3770k CPU , 16 gigs ram
Echo Gina 3G
Windows 7 64 bit, Sonar 8.3.1, 8.5.3 and Sonar X2a 
Lots of plugins and softsynths and one shot samples
Behringer Mon800
Gauge ECM-87, MCA SP-1, Alesis AM51
Presonus Eureka
Mackie HR824's and matching subwoofer

If the crossbleed is very subtle, as you say, then it's not the What U hear-, or Stereo Mix-setting that causes it, I guess (??). Those settings give a real double tracked, loud result.
Then it might be genuine crossbleed, and AFAIK that is due to the card itself, it's poor quality (and some question marks again).

SONAR PE 8.5.3, Asus P5B, 2,4 Ghz Dual Core, 4 Gb RAM, GF 7300, EMU 1820, Bluetube Pre  -  Kontakt4, Ozone, Addictive Drums, PSP Mixpack2, Melda Creative Pack, Melodyne Plugin etc.
The benefit of being a middle aged amateur is the low number of years of frustration ahead of you.