I run XP Pro on my Compaq EVO W4000, which is about four years old. I have recurrent problems which show up in the running of various programs.
1. A great deal of the time the computer operates VERY slowly compared to what I've been used to. This shows up in Quicken, in Quattro-Pro, and on the web (accessed with either Netscape 7.2 or Mozilla Firefox).
2. Sporadically, the operating window will jump to the previous state, as if I had clicked the left arrow. This will often happen when I first try to input into the current window--perhaps only by clicking on an input box--or sometimes later (see Mudcat behavior, below). I can then return to the window where the problem occurred by clicking the right arrow. I may be all right then in the "problem" window, but then again it's not uncommon for this to happen four and five times in a row before I'm able to do anything that sticks in that window. Then I might go a week before it happens again. In Mudcat, if it happens when I'm preparing a post, the part of the post already typed in may be there upon my return, or it may have disappeared. This may happen in Mudcat in the middle of preparing a post, or on trying to submit. This happens online, in Mudcat and at other sites too. Doesn't seem to happen to me in Quicken, but it does in Quattro-Pro, as well as online with Netscape or Firefox. I've mentioned this one here previously.
Seems to me there was another problem too, but my biological memory fails me. I don't expect anyone here to diagnose and cure THAT for me.
All of this (computer stuff) happens despite my having cleared the computer with Ad-Aware, Registry Mechanic, Easy Spy Remover, and Norton Antivirus. LOTS of free HD space, and HD kept fairly well defragged.