You should be able to order a replacement by logging into My Virgin Media at the top of the page, or by using this direct link Order new remote
If the links aren't working either clear your cache and cookies or try a different browser
You can also try the TV Faults option when dialling 150 or 0345 454 1111, but best to call at 8am -10am, or afternoon teatime to avoid call queues
For now you could download the TV Control app and use that until you receive a replacement remote
Regarding your forgotten password, you might be able to change it by logging into My Virgin Media > Update settings > Account details > Memorable word > Telephone security details and editing the field.
The memorable word would have been set up when you first signed up with VM. It should be in your original documentaion.
To help jog your memory the memorable word is usually something along the lines of mothers maiden name, place of birth, name of first school, favourite song or band, favourite food or name of your first pet.
When calling if you don't input any characters from your memorable word then an agent should pick up the phone and ask you other account related questions to validate you.
Have your bill handy to help answer the questions. They will also be able to update the memorable word for you providing you pass verifcation, if not they can send a reminder through the post.