Monitor Flicker

[RichM499]

ok i've long been a musician and as such i have high-end powered speakers and subs surrounding my computer and monitor (its also magnetically shielded .. well the case is.......) ANYWAY... i used to keep my speakers a decent distance away (about 20 inches or so).. but while moving my studio room around i placed a 4x12 guitar amp cabinet next to the computer and monitor while it was on.. ..... in case you didnt know 12 inch guitar speakers have big magnets....... .... x4...... ANYWAY.. i figured thats what caused the flickering that i just noticed today (about 4 hours after the move)... it doesnt happen constantly.. just occasionally horizontal lines about 1mm to 20mm thick flicker on the screen... and more than one at a time... like 5-30 at a time... random places also... (refresh problems???)... any help would be appreciated...