This is usually a sign of pending system failure, often the power supply fan, the CPU fan, or the bearings in the hard drive. Upon arriving on the scene of a computer with such symptom, I place my hand behind the computer's power supply and feel for airflow. If there is no airflow, then the power supply has failed or is failing, and needs replaced. This is usually a fairly inexpensive repair, depending upon brand of the computer and size of the power supply. 

The second action I take is to open the box and check the CPU fan and to listen for the reported noise. If the CPU fan has failed, the CPU will over heat and the system will begin having errors, locking up, or shutting down. If the noise is coming from the hard drive, this is a sign of an impending failure. If the drive has not already failed, it is time for performing an immediate backup or transfer of important data over to another media or hard drive.

Unless you have had a computer crash, losing days, weeks or months of needed files and data, you probably do not appreciate the importance of a full system backup on a regular basis. Tape drives, CD Rewriter units, internal or external Zip or Jazz drives, or the good old-fashioned floppy disk can be used to back up data from your computer. What ever you choose to use, be sure you keep to a regular schedule and verify the data after it is backed up. Many folks with back up systems fail to test their system to be sure they really do have their data backed up. Unless you check your backups, and this can often be done automatically by the same software, which performed the backup.

I can’t begin to count the number of times that I have entered a place of business where there was a tape backup drive where the same tape had been used over and over again, or worse yet, the owner of the computer did not know how to find or run the backup program. I visited a new client once where the same tape had been in the computer for over two months and the log file showed failed backups for the past three months. As one of my first actions, I recommended the purchase a new set of tapes. I established a daily backup schedule and suggested they designate one of their employees as the person responsible for changing out the tape each day.

A somewhat new method of backing up a computer, or an entire network of computers, is off-site backup using the Internet. Files are encrypted on the client's computer, and then sent across the Internet using a high bandwidth connection to the backup server located elsewhere in a secure environment. This is not something to replace the need for a local full backup of your system, but you can back up key data files, such as your "My Documents" files, email folder, accounting data, etc. weekly, daily, or even several times a day. If you have a file corrupted by a virus or erased by human error, it is a simple matter to restore the affected file by running the backup software to retrieve the file from the backup server.

One company in San Antonio that is offering this service is E-commercial.com. I was testing this service earlier this year when I lost a partition on my hard drive. All of my email and website work was contained on the partition which went "poof" after I fixed some errors which had been reported on the hard drive during a routine scandisk. I replaced the affected hard drive and then ran the backup software to restore the missing folders onto my system. Instead of losing days or weeks worth of work, I was able restore all my files up to the last backup performed only a few hours before. 
 

There are other companies offering this type of service, including one in Louisiana, called Data Protection Services. I have tested this service, found it to be reliable and pretty much automated, but once I exceeded 100mb of data to be protected, it began to bog down. If you miss a daily backup, an email is sent to you asking if there is a problem. Their customer support was superb, with fast response via e-mail or phone. 

Neither company recommended using this type of service unless you had cable, DSL or at least ISDN for the connection to the Internet.  If you are interested in this type of service, visit one of these company's websites, or do a search for "off-site data backup" in your favorite search engine. 

But regardless of your decision, it is time to start backing up your key data today, before your system starts making funny noises and you have to call in a consultant to pick up the pieces or sending your drive to one of the many data recovery computers to save the data off of the hard drive if possible.