I know this one is already posted but this one is different. I got this message during boot up: Checking boot system in IRQ 01 . . OK "Invalid System Disk, Replace Disk then press any key" I don't know what to do, i have done every thing that I read on the net and other post but still I cannot able to fix it. About my computer : Windows Mellinium processor: Pentium 3 I have a CD-Rom 56X speed A floopy disk I have an Anti-Virus Chip Does anyone can help me to resolve this problem. There is no CD or a floopy disk inserted on any of my drives when this messages appear. And also I'm not good of touching those hardwares installed in my computer. Thanks in advance.