well in the future if you want to use a password program to protect the entire hard drive i highly recommend ‘TrueCrypt’ ( http://www.truecrypt.org/ , it’s FREE Open-Source software … much better than commercial stuff )
i mainly use it as a file container myself. (i.e. it can make any file (with any extension) you want and load that file into TrueCrypt and it will work as another drive letter … so basically you could make a 4GB file called ‘MyEncryptedFiles.ISO’ and ‘mount’ it with TrueCrypt and in windows explorer it will show up as another drive letter and then you can copy whatever files into it you dont want people viewing)
p.s. i been using TrueCrypt since 2005 and it’s never failed on me even once (NOTE: i never used it’s ‘whole drive encryption’ feature myself but im sure it’s reliable )
as for the Plextools stuff… odds are if you forgot the password the data is history cause i doubt they put a backdoor into it… so in other words your probably going to reinstall WinXP , get data off the encrypted drive, format it and load Vista back onto it etc… or maybe install WindowsXP from that one program (i forgot it’s name but it acts like a ‘virtual pc’) and possibly get your data back that way… but like i say if you forgot the password, odds are there aint much anyone can do besides bit the bullet and deal with the data loss.