A question to toss out - did you use one of the "canned" charts of accounts that come with peachtree or did you build your own?
I ask because if you picked one from the list, you should be fine entering payables, bills, etc. If you chose none and built your own, you might be seeing strange results because of the settings for default a/r, a/p, payroll, etc. accounts.
Also, you might want to go to "options, global" and uncheck the boxes "hide general ledger accounts" so that you can see what accounts are defaulting on the screen. You can always hide them for specific users if you need to, but I definitely prefer to see those.
Also, in any screen you are entering a transaction, you can click the "journal" button at the top to see how the transaction is debiting/crediting.
Don't forget good ol' paper, pen & Mr. T - (t-accounts, where you draw a T for each account and work out on paper how a transaction needs to post) when you are having trouble figuring out what SHOULD be happening. It has helped me alot over the years, yet alot of people forget about it when faced with technology.