Okay i just got my computer today it was used. I was having problems with the CD-Rom not working so i decided to switch out the CD/DVD writer in my other computer and put it in it's place. Okay i put that in place and it's working so i feel good. Well now as the screen starts to boot it starts saying it can't boot for some reason. Well i went to the bios to see if i could change something and maybe i touched something that i shouldn't have. Anyways everytime i try to turn on the computer it says "PXE-E61 media test failure". Then when i press enter to continue it says "Operating system not found". So if someone can help thanks alot.