That sounds all too similar to what happened to my dad's HP. I lucked out and found a dying CDRW drive. More ideas are presented in this link -> http://forums.cnet.com/5208-6122_102-0.html?forumID=44&threadID=241746&start=0
I started last night having very slow start up when I turn my laptop on. It is first a black screen for 5 minutes then the windows xp screen for a few minutes (without the hard drive light on) then shows desktop wallpaper then after another minute my icons appear. It is taking a grand total of 15 to 20 minutes to complete. I have try to start up in safe mode and it is under 2-3 minutes. I have read the other posts and turn off what I could in the start up and the services menus of msconfig. I have ran an Ad-aware scan and a Spybot scan.I have use Mcafee virus scan and Trend Micro online HouseCall scan and both are clean. Last night after problem showed up I did a system restore back to two weeks ago, but the problem is still here. I am running out of ideas. Once the start up is done the system seem to be running fine.
System info: HP Pavilion 5375 Windows XP Pentium 4 2.4 Ghz 448 MB of Ram 60G HDD replaced last year. McAfee security center. Ad-Aware SE Spybot. I keep spybot, AdAware update twice a month. thank you for your help.