Q I think I may have a bad power supply unit on my Dell PC. But, so I can be sure, what are the symptoms of a bad power supply?
BRETT SMITH, PLYMOUTH
A Fortunately, there are plenty of warning signs of an impending failure in your PC's power supply, which converts alternating current from a wall outlet into direct current that your PC can use.
But remember, a bad power supply should be replaced, not repaired. Some electronic components inside can store a big enough electrical charge to be dangerous.
Some signs of power supply failure are obvious: cracking and popping noises when you start the PC, a spark or smoke in the power supply itself or the smell of burning electronic components.
Other signs are more subtle: When you turn on your PC, you should be able to hear the cooling fan start to run and the hard disk start to spin. If those things don't happen, the power supply may be going bad.
Other telltale signs that indicate the PC is getting only intermittent power:
The PC doesn't start up properly, or abruptly reboots while in use.
You receive error messages about the PC's memory.
The hard drive makes clicking, humming or beeping noises.
Q I recently switched from Verizon to Cox Communications for home Internet service. Since then, I have been getting 50 to 60 spam e-mails per day.
What happened, and how do I stop it, short of changing my e-mail address?
JIM HOLLADAY, SAHUARITA, ARIZ.
A You need to change the settings on the Cox Communications spam filter (which comes from a company called SpamBlocker).
The filter scans incoming e-mail before it reaches you; the settings you use determine how thoroughly it blocks spam.
You can choose to automatically delete incoming spam (with the risk that you might lose something that's not really spam), have spam forwarded to the SpamBlocker folder in your Cox e-mail (be sure to check it often because that folder is emptied automatically after 21 days), or have the incoming spam labeled "spam" and sent on to your inbox (where it will stay until you choose to do something with it.) For details, see tinyurl.com/87c6hu2.
Cox also offers tips on how to minimize the amount of spam you receive (see tinyurl.com/85xk575), including the sound advice that you should never click "unsubscribe" on a spam e-mail in the belief you'll be taken off a mailing list. That just proves that your e-mail address works and guarantees you'll receive even more spam.