Sometimes when I boot up I get very strange noises. I hear three short noises from the MoBo and monitor remains blank. When I turn off and on again, everything is normal and I get into windows. What does the short beep mean? Should I be concerned about this or not?
You should be concerned. As far as I know the most frequent cause for three short beeps upon POST is bad ram memory. Now it is a bit odd that you are sometimes able to turn on you machine. Maybe resitting the RAM will solve the problem. Also, try to omit some ram modules (if you have more than one) to see whether the beep remains.