It depends on what your privileges level on that account were. If the account you can no longer log into was the administrator account for the PC, you should probably wipe and reload your operating system. If the account was a user level account, log into the administrator account and you should be able to copy and paste the files from that account to your CD/Rom or a thumb drive. Be sure to scan them with an anti-virus program first.
If the “main” account has administrator privs then you should change the way you use your computer. The admin account is for updating the PC and loading programs. NOT for day to day business. Don’t surf on the Admin account. Don’t use email on the Admin account. When you do either you are...