you really can search for thyis info....
short answer - yes. can be done quite easily.... and I have achived this.
1. proper grounding of computer, psu, auido equipment.
2. good quality supply/power lines (NO cig lighter crap!) run a wire from the battery direct.
3. good qual sound card
4. remove filter components from PSU (documented on my website)
check my (old) system at my website. I say old cause im about 30% thru buiding my new system with DC-DC....