Missing account in Login page


Today I turned on my MacBook Pro 13" and got to my logon page. My main account was (IS) missing. I can see my other account as well as Other. The missing account, is the administrator one. So I tried some tricks, but I don't like the result. I logged with the root account, and added a new User, with the same folder and the same UID. So now I see the new User log in form, and I can enter it, getting all the files and all the things that I had in the other account. But it costed me in speed! Now my MacBook is slow as hell. It takes 80 seconds to boot up plus another 30 seconds to get ready for use. Yesterday I could do it in less then half time. Another thing I don't like is, if I go to Settings/Users And Groups (don't know how it's called in the english version) it says to me that I'm logged with my old account (the one that doesn't show up in the log on page) but if I want to do some administrator stuff it wants my new account password! Not that it prevents me to use my computer but, well, I just don't like it... and I don't know if it is related to the slow fact.

Sorry for my bad english, I'm an italian folk with barely a B2 english level.