#1
HI. i just got a line 6 spider iv, and when i plugged it up, i found i was getting a hell of a lot of feedback. to begin with, i thought it had something to do with my broken guitar lead, so i replaced it, and still got feedback. after looking at sites, i found out it could have something to do with the fact i use my amp in the same room as my computer, which could cause the feedback. Is there anything i can do to help reduce the feedback?

PS: I know its got something to do with the computer or the room, because i tried the amp in my conservatory (which has NO electrical devices plugged in, and i only get a tiny ammount of feedback
#2
line 6 spiders have a noise gate.. look through the manual on how to activate it..

but the main source of your problem.. not just hoping on the bandwagon but know from experiance.. it's a spider.lol
#3
ye, AC is a bitch.
you are probably runing the amp on the same power supply of you computer. or maybe your room just as some major voltage cables that pass trough.
try to connect your amp in a different part of the house