回复：我用的是xp，光盘驱动器符号突然没有了，重新装也不行

Make sure the CD-rom is not broken and the paralellet cable too. And check the connect is not loose.
If in the bios you can see the CD-rom then the CD-rom is ok and connection is ok too. That means theproblem with the operating system then you need to recheck the CD-rom jumper.