For nearly a decade I used free sequencers and cheap DAW's without playing a real (physical) instrument. So, believe I understand where you coming from. For the longest time I just used samples I found on the internet or ripped from CD's.
The component's of the heavy metal guitar I know you want are overdrive
http://en.wikipedia.org/wiki/Overdrive_(music) and power chords
http://en.wikipedia.org/wiki/Power_chord. That combination gives the guitar a dirty, but full sound (wide frequency coverage). I don't have the exact answer you are looking for, but I hope the following can provide some direction until someone (who has more experience than I do) can provide a detailed answer.
The great thing about the modern world of DAW's and powerful audio interfaces. There are many, high quality softsynths (software synthesizers) available that can give you nearly the precise sound you want. Depending on which product you purchased from Cakewalk you may already have a similar softsynth. I would suggest looking through your softsynth libraries (Dimensions has quite a few guitar softsynths.)
Assuming you don't have the exact sound you want and don't have the budget to run out to buy the ideal softsynth package a common technique I frequently use is called layering. I will copy the same midi track several times and have that output play through several different softsynths at the same time. For example your heavy metal guitar might sound good from a combination of playing through a distorted guitar, steel guitar, and overdrive guitar (all in the com
mon MIDI wave tables... usually in your audio interface, Cakewalk Sound Center, etc.). You may have to alter the tune of the instrument or transpose the midi notes to get the instruments to have a similar tonal output for a given note. I sometimes will intentionally leave layered instruments at different pitches to get a fuller sound out of a given note. I also frequently run the outputs to a shared bus so I can apply a filter like reverb to help 'blend' the sounds.