every time I boot up my Windows XP pro desktop, about 10 minutes later, my computer runs very sluggish. and I can barely do anything. winlogon.exe is using 99% CPU the entire time. A web search turns the only related result: https://support.microsoft.com/en-us/kb/329897 but it says it only applies to Windows 2000 machines, this is Windows XP with this problem. all search results lead to Windows 2000 based machines, nothing at all for Windows XP, and none of those processes were found on my machine. What else could be the problem?