Do you have a router? (more than 1 pc hooked together?)

When your DSL gets disconnected, do you come back to IRC with a new IP number?
My dsl modem has lights for 'outbound packets, inbound packets, & connection to the 'office'.... when these disconnects occur, are you seeing red/green similar lights ?

You say, "i get disconnected from my DSL everytime I install MIRC"
Is mIRC installed or not ?

You mention past virus, have you reformateed and reinstalled everything from 'fresh' or from a restore date, or a back up ??