Boot into Windows as administrator

[WojtasRed]

How can I do this on Vista Ultimate x64?

[DanTheBanjoman]

Select other user and type administrator and the corresponding password?

You could try to Google before asking everything.

[AsRock]

At least one of the accounts have to be Admin if you don't know maybe you should not be askig ?.

You can check what the names are by going to the users folder.

EDIT:
Use the name you installed Vista with. Like if the name was WojtasRed that would be the account name and admin account.

[WojtasRed]

tanx!

[MainframeTM]

I try this on XP & it always says my passwords wrong

[Snake05]

I try this on XP & it always says my passwords wrong

You set up the admin password when installing XP, but most the time people believe it is for their individual account and not the Administrator one. As for Vista, like stated before, the initial account created is an administrator account, and if necessary, you may need to right click certain programs to "Run as Administrator"

[cdawall]

I try this on XP & it always says my passwords wrong

go in under another account and delete it and make a new one