I have had a Windows 7 Core I7 system running at home for several years and performance has been fine. Lately, the system has started running very slowly and I can see the disk activity light stays full on for extended periods. I looked at the Performance Monitor to see what was bogging things down and it seems to be PID 4, the System process, that is using all the disk resources.
I did some searching and found some similar posts in various places but most of those posts are several years ago and pretty generic, like check your disk for errors. I have a disk monitor that says my disk is perfect. I ran the troubleshoot which cleaned up a bunch of temp files. I removed a few startup programs. Nothing has really changed on my system in the last few days but it sure is acting different.
I tried rebooting and boot time seems to have become excessively long. If I leave the system alone for a a while the disk activity slows down but as soon as I web browsing, the activity goes way up and everything runs slowly. Again, this is new behavior within the last two weeks.