[Dazarath]

There are a couple of ways to do this, depending on what you want.

If you just want a backup of the database, then do the following:
1) In PT (in the one you want to backup) go to File > Maintain Database Names.
2) You will see a list of databases (or maybe just 1). Look under "Type" for the database you want. It will either say "Access" or "PGSQL".
3a) For Access: Look under "DB File/DB Name/DSN". It might say C:\Program Files\Poker Tracker V2\ptrack2.mdb
4a) Copy that file, as well as hhdb.mdb to your other computer.
3b) For PGSQL: In PT, go to Utilities > PostgreSQL Database Functions.
4b) Select the database you want. Use the "Backup" button. Copy the resulting backup file over to the other computer.

If you actually want to merge the HHs from one database into the other, then you need to do something slightly different. I think the following is probably the best way:
1) Go to Utilities > Export Hand Histories to File
2) Select the criteria for the HHs you want to export (leave them all blank if you want every HH).
3) Export them.
4) Copy the resulting text files over to the other computer.
5) Import them into the PT database.

If you still have questions, or would like something explained in more detail, feel free to ask.