问题如下，试了好几次，都是这个问题。
Basically, I got my X61s with vista basic, and I want to replace vista with XP pro. What I did are:
1. Connect it with an external DVD rom through USB port.
2. Login to BIOS setup and change the harddrive to compatibility mode.
3. Boot from external DVD drive with XP pro CD software
4. Get the C drive formated and start loading XP files.
So far so good until this step, however,
5. After the startup files were loaded, the system is rebooting and installation is continued.
6. When the system rebooted for the next step installation, it can not find the required files from CD software disc, it prompts me to input the path, it looks like it doesn't know what the drive letter for this external dvd drive, I tried a:, d:, e:, etc. none of them works. and the installation can not be continued. This is so weird to me.
哪位高手给些建议，应怎样解决这个问题？
多谢！