China DOS Union

While installing DOS 6.22 in Virtual PC, I ran into the following problem

WARNING

YOUR HARD DISK INSTALLATION WAS SUCCESSFULLY COMPLETED.

Continuing with the Uninstall program will remove MS-DOS 6.22
files from your hard disk and will replace them with your original DOS.

To restore your original DOS, press R.
To exit, remove the Uninstall disk from drive A: and press E.

After pressing "E", the same prompt still appears
What should I do?

Finally got it sorted out
It took a whole day
I've got exams coming up too
But I still learned a lot