Hi there,
Put your .pst on a drive that is not windows 7 C drive (like e Drive) I put mine in my Docs drive. Use your .pst as your main file from were it is (it doesn't have to be in C drive to run data and store data). You need to go to control panel / Mail 32 bit / Double click and if your Outlook is configured you will see your profile. Double clic the profile and add the data file (pst) (Browse to folder that you copied it). After that you can delete the other data folder created by default in C drive.
If you did not create a new Outlook account, open Outlook then close it without creating account. Go to controll panel / find mail 32 bit, double clic, create a profile and browse for your data file that you copied to another drive.
Hint:
I changed my the name of my mailbox .pst to backup.pst so I can easily find it.
If you only have a few entries in the original .pst created by Outlook, you can export that .PST and import that one instead of Importing your large