Sysmon, System Monitor to diagnose slow PC

If I want to find out how resources, e.g. CPU, Memory, Disk I/O, are being used/abused on a sluggish PC, what sysmon items should I be looking at?

Thanks, DaveBo

In windows XP, just get the ctrl-alt-del window, and go to view->columns. This has a lot if info (all you mentioned).
For an actual program try www.3dsoftware.com/sandra