[prmckay1]

I just solved a Dell Laptop's Hum w/ a 3 prong to 2 prong 'Ground-Lift' adapter.

I use an 1/8 Stereo to XLR (M) w/ Shielded Cable to solve my HP Laptop's Hum.
This Shielded Cable has solved 3 x 'Desktop/Tower' PC's Hum problems.

Just encountered an Equilizer that picked up a radio station (90.1Mhz) -- The EQ had both XLR and 1/4" Inputs -- I was using the XLR -- but ended up adding the 1/4" to it (nothing attached to the other end) and the Radio Station was gone! (I even attempted the Ground Lift) -- Their Engineer (Peavey) suggested that as a solution.

And of course the old standard -- 'Dirty-Power' problem - reducing the 8K of the EQ will help -- but the Freqency's that you lose are detrimental to your sound quality.

Agree w/ jdavia -- Isolating your problem hum is 1st priority - and the hardest as well!