Megadeth- Shadow of Deth- The system has failed- 
Tabbed by SPECKTOR- 100% CORRECT! Rhythm Guitar Part!

Riff 1-

|---------------------| (Palm mute)
|---------------------|
|---------------------| 
|---------------------| 
|--5-2-3-5-2-3-4-5----| 
|--3-0-1-3-0-1-2-3----|  (Played several times)

Riff 2-

|---------------------|  (clean- no palm muting)
|---------------------|  
|---------------------| x2
|7--5--4--3--2--------| 
|5--3--2--1--0-5------| 
|--------------3------| 


Riff 3-

|---------------------------------------------------|
|---------------------------------------------------|
|---------------------------------------------------|
|-9-9-9-9-9-9-9-9---5-5-5-5-5-5-5-5-----------------| 
|-7-7-7-7-7-7-7-7---3-3-3-3-3-3-3-3--7-7-7-7-7-7-7-7| (pm)
|------------------------------------5-5-5-5-5-5-5-5|

|---------------------------------------------------|
|---------------------------------------------------|
|---------------------------------------------------|
|---------------------------------------------------|
|8-8-8--9-9-9--15-15--------------------------------|
|6-6-6--7-7-7--13-13--------------------------------| 

Riff 4-

|---------------------------------------------------|
|---------------------------------------------------|
|---------------------------------------------------|
|---------------------------------------------------|
|12-12-12-12-12-12-12-12--10-10-10-10--10-10-10-10--|(pm)
|10-10-10-10-10-10-10-10---8--8--8--8--8---8--8--8--|

|---------------------------------------------------|
|---------------------------------------------------|
|---------------------------------------------------|
|---------------------------------------------------|
|9-9-9-9-9-9-9-9--8-8-8--7-7-7--5-5-----------------|
|7-7-7-7-7-7-7-7--6-6-6--5-5-5--3-3-----------------| 

Then finish by playing riff 1 again!!!