Fast Forward's Help File

Q We use a few e-mail accounts at home. How can I check all of them in one e-mail program but keep each account's messages separate?

AIt's easy to do this is if your accounts use a setup called IMAP (Internet Mail Access Protocol). In that case, your mail program should automatically keep each account's messages, received as well as sent, in a separate set of folders.

Most mail services, however, run on the older, less-flexible POP (Post Office Protocol) system. With POP accounts, every message usually lands in the same inbox. You'll have to set your mail software to sort them into separate folders based on the address to which each e-mail was addressed.

In Windows, go to your mail program's Tools menu and select "Message Filters" (in Mozilla Thunderbird), "Rules and Actions" (in Microsoft Outlook) or "Message Rules" (in Outlook Express and Windows Mail). On a Mac, open Mail, go to the Mail menu, select Preferences and click on the Rules icon.

Even then, everyone's sent messages will probably stay in the same "sent" mailbox. You might find it easier to set up a different e-mail program (or create a separate Windows or Mac user account) for each person who uses the computer.

I heard that Microsoft Excel 2007 has an arithmetic problem: If you try to multiply numbers that should result in 65,535, the program says the answer is 100,000. True?

True. Try, for example, multiplying 77.1 by 850 or 10.2 by 6,425, and Excel 2007 will display 100,000 instead of the correct result, 65,535.

Microsoft has released a "hotfix" download to correct this problem, available at its tech-support site ( http://support.microsoft.com/kb/943075/).

Rob Pegoraro attempts to untangle computing conundrums and errant electronics each week. Send questions to The Washington Post, 1150 15th St. NW, Washington, D.C. 20071 orrobp@washpost.com.

Turn to Thursday's Business section or visithttp://washingtonpost.comanytime for his Fast Forward column.