I am using pc with Win98 OS. currently I cannot Start my PC. Message BOOT DISK FAILURE, PLEASE INSERT SYSTEM DISK AND PRESS ENTER appear. After insert Win 98 start up disc the PC still cannot start. SACNDISK and CHKDSK did not find any error on my HD. Directory in C: did not show WINDOWS and any work files. Our company technical support told me that my HD is corrupted. Because of many important file in it, I exchange my HD with my colleague PCs. The result is my HD is OK (boot normaly) at another PC but my friends HD facing same problem in my PC, I called our company technical support again and explain what I have done. They guess that my Mother board is corrupted. Anyway I want to know what is the real problem is it virus attacked, motherboard error or data cable error and I would like to thanks to all who can give suggestion and advise.