Today a window started to appear on my screen stating "Windows File Protection. Files that are required by Windows to run properly have been replaced by unrecognized versions" and asking me to insert my original XP Pro CD. I checked the system files. The only unrecognized files this year are tifsfilt.sys and timntr.sys, both dated April 14th, and both apparently related to Acronis. I believe on that date I downloaded the latest build #826. When I cancel the error message, the computer seems to be running OK, but the error message still concerns me. System Restore does not have a restore point from that date, even though it is set on "automatic". I do not have an original CD since XP Pro came loaded on my computer from Dell. I have Svc Pack 2 installed.