An 18 second start up? That's really good for XP!! I'm guessing you are not counting the DOS/DIOS initiation, because PC's require at least 18 seconds to get to the Blue Windows Splash Screen with the fill bar.
Anyway, I think I can help you clean up your bootlog problem. I'll be asking you to run 2 different Registry Cleaners followed by a handy Rootkiller Utility. All 3 of these programs are trusted FREEWARE utilities and won't cost you a dime.
Programs needed: CCleaner by Piriform, COMODO Registry Cleaner by COMODO and TDSS RootKiller by Kaspersky Labs. Download them and get them ready to run.
Steps to take:
1. Run CCleaner in CLEANER mode - Make sure the following boxes are checked under [Advanced Settings] -Old Prefetch data, -IIS Log Files, -Hotfix Uninstallers then [Run Cleaner]
2. Stay in CCleaner and go to [REGISTRY] mode and make sure all the boxes are checked, then [Scan For Issues] ...wait... [Fix Selected]
3. Next, open COMODO Registry Cleaner program - [Scan My Registry]... wait... [Fix All Issues] including any -Unsafe Entries (you will have to check this box manually)
4. Now run the tdsskiller utility. It will run in a DOS window.
5. Rooboot your system, do an F8 interrupt - Select [Enable Boot Logging] - Continue start up
6. When XP is ready - Locate ntbtlog.txt file under C:/Windows - Open the file and be amazed! Your failed driver attempts will be greatly reduced. (You might have a couple remaining, but nothing to worry about)
Try it.