Recording issues with X2

Me again. I'm running X2 Essential on an Event, AMD A6 3650 w/ Radeon HD graphics 2.6ghz. 16GB ram.
Still having trouble getting tracks in synch. Record the drums first, then usually putting down guitar, but recorded bass this time. They sound good, but now trying to put the guitar in on a third track and the guitar is all whacked out of synch. I have messed with the buffer controls and latency controls to no avail. Forgot to mention using a Tascam 1800 interface for all inputs. I'm ready to throw it out the window, but I know it's user error and not the equipment. HELP! When I do "lower" the latency and or buffers in preference, I get dropouts.

Meaning out of sync. When I try to record the guitar while listening to the drum and bass, on playback, the guitar is a 1/4 to 1/2 beat behind the rest of the music. Sometimes it will get a whole beat behind on its own half way through the song. I've tried adjusting the latency and buffer settings but it keeps happening. If I adjust the settings too low, I start getting dropouts which is why I posted my processor and ram thinking I don't have enough power to run Sonar. I'm not a tech guru, I'm a musician and I did research for recording equipment thinking I got what I needed. I just want to record some basic stuff and have some fun.

Are there a bunch of effects loaded into any of the tracks or onto any of the buses?
 
You could test out the potential interference of any such plugin quite simply: just prior to hitting Play, first hit the letter 'E' on your computer keyboard.  This will toggle the 'Bypass All Effects' function in Sonar, so if any plugins were causing problems bypassing them and then hitting Play should clean up the sound (though you wouldn't hear the effects).
 
SOOOO, if you DO run through listening after bypassing effects, what happens?  Is it better?  If so, then one or more of your plugins is likely not meant to be used during recording/tracking, but is instead meant for mixing/mastering.
 
Can you please perform the above test and post back the results?  (also, after running the test, hitting 'E' again will toggle the effects processing back on).
 
Thanks,
 
Bob Bone
 

Are the drums and bass MIDI (through a MIDI keyboard or soft synth?) or audio?
What is the sample rate for SONAR and your interface set to?