Q About a month ago, I noticed that my 2004 PC running Windows XP was taking longer to start up and connect to the Internet. On the recommendation of a local store, I purchased the Iolo System Mechanic Professional program to help speed up the PC. When I began installing the Iolo program, I was told to uninstall my anti-virus software first, which I did. But I also read online that I should delete some anti-virus components that might remain on the PC by altering the Hkey files, so I did. Then I installed Iolo.

Now my PC is slower than ever and I'm getting error messages about the check-disk function (Chkdsk) and about a file or directory on my hard drive that is corrupt and unreadable. What can I do?

HELYNN SCHUFLETOWSKI, EAU CLAIRE, WIS.

A Your PC may be suffering from a flaw in Iolo's System Mechanic program, or from your altering of the Hkey files. Those files are part of the PC's registry, a database of computer settings that can cause trouble if altered incorrectly.

In a review of the Iolo program earlier this year, the Notebook Review website said Iolo "can run so many consecutive and powerful PC utilities that their combined effect might 'over-clean' your system and leave applications -- or the PC -- running improperly." For details, see tinyurl.com/264ph6y.

If the Iolo program is to blame, you might be able to reverse the changes it made via a rollback function in the software called "SafetyNet." For details, see tinyurl.com/22s55e5.

If the Hkey changes that you made are the problem, try repairing Windows XP using the Windows CD that came with your PC. First back up your most important data on an external flash drive or hard drive, then try a "Repair Install" of Windows XP. See details at tinyurl.com/r1cg.

Note: The repair will erase all Windows improvements you've downloaded for the last six years. Use Windows Update to reinstall the fixes for all the flaws and security risks discovered since then.

Q We have a 2002 Canon Multipass F50 printer that doesn't work with the Windows 7 PC we purchased. Canon and Microsoft say we need to buy a new printer. Do we?

JUDY WUOLLET, ST. LOUIS PARK

A Canon doesn't offer the driver software to make your old printer work with Windows 7, so the best solution is to buy a new printer.

Alternatively, there may be a workaround. If you have the "professional" or "ultimate" versions of Windows 7, Microsoft offers free add-on software called "Windows XP mode." XP mode might enable your printer to run, but not conveniently. Windows 7 documents would have to be transferred to XP mode for printing. See tinyurl.com/yl2ucno for details, and tinyurl.com/crgfls to download.

E-mail tech questions to steve.j.alexander@ gmail.com, or write to Tech Q&A, 425 Portland Av., Minneapolis, MN 55488-0002. Include name, city and telephone number.