While using my system i am seeing that the display in my Monitor is going off for a few seconds and then again turning on. This phenomenon is being repeated for a gap of 1 or 2 hours while using my system.I am using a Dell S2240L monitor and has already called the DELL Customer Care for monitor issues and they have said that there is no issue with the monitor according to them and the issue lies somewhere else.Please advise what can be the reason for this issue.