XP doing everything wrong

OK, all was well until a few days ago. Now, my XP on a Dell takes forever to boot up, meaning a good 10-15 minutes. The little green "reading" light is constantly on during the boot process. My desktop icons won't stay put, even though I've done all the locking/grid stuff you're supposed to do. I get an error when I try to change my theme to Windows Classic. The latest thing happening is an error box saying it cannot find "null". My font settings have been changed. All my recently used apps in my Start menu have gone AWOL. For awhile my wallpaper wouldn't stay put, and actually disappeared from the pull-down list, so I would have to browse to re-apply it. That, for now, is staying where I put it.
I have run, in safe mode with restore turned off, Avast; Spybot Search and Destroy; Adaware. I thought removing IE7 may have caused my problems, so I have just been to the M$ site to reinstall it.
Any help would be very much appreciated.

 

Hi,
It does sound like an infection but with all the scans you have run it's difficult to see what you can do. Have you looked at the dealing with malware section on this site ?
I would get myself an external hard drive(they are very affordable now] back up all my precious info onto it and then reinstall my system. That would be a good point to start using a disk imaging programme, I use macrium reflect free, and you could put the images on the external. Then if anything like this happens again it is only a matter of 20 to 30 minutes to get the whole of your system back on.You lose nothing that was on your PC at the time the image was made. Of course fairly regular image making is the ideal as you will be up to date. I make a note on notepad of any changes since the last image so that I can get back to exactly were I was when disaster struck. I have had to use macrium on two occasions and it has dug me out of a hole. Even if you can clean an infection [assuming yours is] you can never be 100% sure it is cured or that you have not quarantined some vital files. With Macrium you are sure you have resolved the issue but you need to start with a clean image. I took a clean image, used the PC for a month then put that month old image on. I then brought it up to date, with the aid of my notes and immediately took another image for use another month down the line. This way I am confident of having a reasonably current image that is clean. I kept the initial image as my day 1 image. Now the only problems I worry about are hard ware related. Malware and software problems just have me reaching for Macrium.
I hope this helps and if you do decide to go the back up route I will help if I can Just send a message.
Good luck...Alex