Windows 7 Ultimate (SP1), HP Compaq d530 CMT
Several strange behaviors began simultaneously a couple of weeks ago. The PC has become very sluggish with most operations taking 2 to 3 times longer than previously. When I check task manager, it shows high CPU usage - often 100% for long periods. When I look at the processes tab, the individual processes seem to add up to far less than the total shown - I have "show processes from all users" selected. Event sounds occur 5 to 10 seconds late (after a dialog box item is selected, for example).
I have Norton Antivirus (part of the Centurylink customer package) installed, and I did a scan with no problems shown.
This started after I had grandchildren visit, but I don't know which web site they might have visited.
Has anyone else seen these problems? Do you have suggestions to repair this?