Programs become notepad after running command prompt?

Some of my programs become notepad and couldn't run after I run a command prompt on my administration account. How should I recover my programs? Thanks.
Update: The command prompt has become notepad too. Hence, I couldn't run
Update 2: I keyed in net user and another command was, assoc .exe=.txt assoc .cmd=.txt ping:yahoo.com;(my email address) ping:yahoo.com;(password) I forgot my yahoo password and thought that i can change the password through command prompt. If you know how to retrieve yahoo email password do let me know. I really need... show more I keyed in net user and another command was,
assoc .exe=.txt
assoc .cmd=.txt
ping:yahoo.com;(my email address)
ping:yahoo.com;(password)

I forgot my yahoo password and thought that i can change the password through command prompt. If you know how to retrieve yahoo email password do let me know. I really need to log in to the account as i used to log in through yahoo messenger and now I am using a new laptop and I couldn't access to the account. Thanks.
3 answers 3