Sure your monitor works with build it test ,, but have you forgot about the cable that goes from your monitor to the computer,, I had to through away a 15 inch monitor because the cable was messed up and I was getting two colors at a time, and I did not bother fixing it becasue I wanted a 19"
,, I don't think formating your hard drive will fix the problem if you already have installed the correct Video Driver / Monitor Driver,, just connect you PC to another monitor before you anything else
cheers