lately my monitor is suddenly displaying some horizontal black lines after i boot up.i actually used my tv to test whether it had the same prob..n it did..so im assuming that my monitor is fine.i had recently installed SP2..i had an error message(blue screen) that told me that it was "nv4_disp"..i re-installed the drivers..it was working fine..but it started to slightly display those black lines again.it previously had totally blacked out..i cudnt see anything on the monitor.i also went into bios n loaded the optimized defaults.that seemed to solve the problem.bt im starting to see the lines again..any idea what actually causes the problem?