Earlier today I added a USB drive a drive letter from my laptop attached to - it seems to replace my hard drive has been in the same letter. Reset the external use of CD-ROM drive letter manager, of course, can no longer see my second SATA drive in order to restart my computer. It has seemed to hang on a black screen with the XP logo and loading bar and - the animated GIF to continue, but does not load, I can not hear any of the activities of CD-ROM goes beyond this point. I tried the BIOS if the CD is recognized and all are identified.

I can start it in safe mode with network support (enter this information in a safe mode) all seem to establish a drive, my first, second and USB drives can read and seems to identify. Checkdsk there is no problem with the report. I have not added any new hardware or change any driver
I believe that attempts to XP, but the experience of all the steps, but failed (only hang) in the message to start XP. In my old computer problems, to solve the updated video driver, but in this case, the machine hung on the stage.

I have reason to competent and just want to know, if someone can suggest the best sequence of trouble shooting. I seem to recall that in Windows 98 you may be forced to boot to proceed step by step to see it fail - can not remember how to do this and not sure if XP has this feature.

I read a lot of response from the proposed use msconfig in safe mode - whether there is plain guide anytime, anywhere - I can start up, you can see, you can set options such as a minimum to start - but I read the reply, it is necessary to change some things or even stop working and security model, it is difficult to resume the use of msconfig - may be a myth and that is why I call on expert advice