They only way I know of getting into dos would be to go
to RUN: Type ipconfig, it will open a dos window for you.
Or, have you tried to go into Log Off. If you log off,
you may be able to go into DOS, and log back on in DOS.
It is not possible to get into DOS from Windows XP in any way, since Windows
XP is built on the NT code base, and has no MS-DOS layer. To get into
real-mode DOS, boot the computer using a Windows 9x startup floppy, or dual
boot with a version of MS-DOS or Windows 95/98.
With that said, you have a couple of options for command-line access to
Windows XP:
1) Boot using the XP install CD and choose "Repair" at the first
opportunity. This will leave you in the XP Recovery Console, where you will
be able to use several text-mode commands for file recovery.
2) From the Desktop, do "Start|Run" and enter the command "cmd" to enter the
XP console, which will allow you to use text-mode commands such as "copy",
"xcopy", or "delete". Or, enter "command" for a 16bit version of the
command interpreter.
****NOTE***
If you boot the computer using a Windows 95/98 startup floppy, and the HD is
formatted as NTFS, you will be unable to read from or write to the HD using
Microsoft-supplied tools, since NTFS is inaccessible from MS-DOS without
third-party tools.