You created a parallel installation instead of an "upgrade". That's why you
can't access these programs.
Can you still boot up in ME? If so, boot into ME and then run an upgrade
install. Now reboot and see if all is well.
If so, you can look in the C:\ to see if there is now a C:\Windows AND
something like a C:\Windows.001 folder. If this second folder exists, (AND
XP boots WITH access to all your programs) then you can safely delete this
newer C:\Windows.001 Folder. You will need to change this entire folder to
"unhide" and uncheck the "read-only" status to delete the folder.