When a storm rolls in and the thunder starts to rumble, certain thoughts instinctively flash through our minds: Are my windows closed? Do I have an umbrella?

But ... what about your computer? A $50 investment can save hundreds -- if not thousands -- of dollars worth of equipment.

According to Gateway representative Wayne Eng, a single tickle of lightning coming through a power or telephone line can fry an entire system.

"[It] could be anything from the power supply to the processor, the memory, the modem, any other video or audio component boards, hard drive, floppy drive, CD ROM ... could be any part," Eng says.

Most consumers do have surge protectors connected to their computers to guard against jolts coming through electrical circuits -- but many don't realize that they may still be vulnerable. Electricity coming through a phone line -- which connects to a computer's modem -- can cause just as much damage.

To protect against both types of surges, use a power strip that has connections for both phone lines and electrical cords.

But even surge protectors aren't fail-proof: Experts recommend turning off and unplugging a machine whenever severe weather is overhead, or when you leave your home for an extended period of time.

Some homeowners' insurance policies cover damage from electrical surges, but nothing can replace lost data and invested time.

A good surge protector should:

• Meet the UL 1449 standard for surge suppressors.
• Protect both communication and electrical connections.
• Offer a lifetime guarantee covering the product and the equipment it protects.
• Feature an indicator light to show the device is functioning.

Additional Resources:

• PC Guide's explanation of surge suppressor quality ratings.
• How surge protectors work, and advice on purchasing a good one -- from PC Webopedia.
• Surge protection tips from TDS Telecom.