Q: I use System Mechanic and scan the computer about once a week. Every time, with my Windows 7 professional-edition computer, there are between 4 and 30 registry errors.

I have two questions. First, what is a registry error? Second, if there are always registry errors, why did Microsoft not design its own program to find them? Is this an example of our friendly giant neighbor's incompetence, or do they just leave some jobs undone so third-party software manufacturers will have something to do?

By the way, there were a lot more registry errors with XP in the old system I had vs. the new computer and new software.

— Frank Mitchell, Seattle

A: The Windows registry is a file that keeps track of configuration information about your computer, its operating system, hardware and applications. When you install a program, information about file locations and configuration gets stored in the registry. By design, that file can be accessed by third-party applications.

A registry error can be of several kinds. The most typical is a pointer that tells Windows a program is in a certain location but it isn't there.

Errors in the registry generally occur because of one of three things, listed in descending order of likelihood: a poorly written program installation application or uninstall routine; a piece of malware has found its way onto your computer; and the registry has been corrupted by a problem with the hard drive.

As for why Microsoft hasn't designed its own registry cleaner, I couldn't begin to guess..

Q: I have been having intermittent connection problems with my Epson 3590 photo scanner. I recently changed to a new computer setup, from running Windows XP to an HP Pavilion bundled package with Windows 7 (64-bit). While I am not exactly a neophyte in using computers, I am definitely not expert in solving deep problems.

For some weeks I had been getting a message on startup saying that Windows Image Acquisition could not be accessed. I would close the window, and there appeared to be no problem with any images. That message has now disappeared, but I have been getting, intermittently, another message: "USB Device not recognized."

Checking into it further, I found that it was the Epson scanner USB connection. After many attempts to resolve the problem I found that rebooting the system enabled scanner activation. However, that workaround did not last long.

— Scott Tomkins

A: Not an unusual problem when upgrading an operating system. I'd bet dollars to doughnuts that you don't have the Windows 7 driver for your scanner installed.

I checked, and Epson does offer Windows 7 drivers for that scanner. Just search the Internet for Epson 3590 Windows 7 driver and at the top of the list you'll find an Epson page that will let you download the software you need. Follow the directions and you should be in business.

Q: My wife's laptop is using Windows 7 (64-bit) and Internet Explorer 8. Recently, for no apparent reason (that I can see), the 64-bit version of Windows 7 is missing, gone south, not there anymore.

When she tries to use the 64-bit version with Internet Explorer 8, she gets an error message stating, "Internet Explorer is currently running with add-ons disabled. Click here to manage, disable, or remove your add-ons." Any ideas?

— Joe Black, Texas

A: It sounds like your issue isn't with Windows 7 but with Internet Explorer 8. (After all, if Windows wasn't launching you wouldn't be able to load Internet Explorer.)

Try this link and see if it takes care of the problem: support.microsoft.com/kb/976915

Questions for Patrick Marshall may be sent by email to pmarshall@seattletimes.com or pgmarshall@pgmarshall.net, or by mail at Q&A/Technology, The Seattle Times, P.O. Box 70, Seattle, WA 98111. More columns at www.seattletimes.com/

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