Sorry but I had to delete a reply to you as it contained a link to the posters own web site. However, he did post a good reply so I repeat it below;
I would update the virus/spyware scanners that you use and then run them in Safe Mode - the spyware scanner(s) in particular, because some spyware is installed in parts that can regenerate each other if one part is removed in normal Windows mode, but not in Safe Mode.
You can enter Safe Mode by pressing the F8 key repeatedly after the memory count and before XP starts to load."
I have an Advent T12 desktop pc, running on windows xp. Each time I turn it on it takes literally 10 minutes to boot up. Ive tried restoring the system to a previous time to see if this solves the problem, but with no success. Any ideas how I can solve the problem? Or even what the problem is?