hhhmmm.....
Well sounds like a couple things.
1)Anytime you try to access a file, not folder, your anti virus decides to scan it, and check for harmful content. Most antivirus WON'T scan a folder, but files. I would check your av options to make sure its not set up to do that.
2)Since your system runs in safe mode just fine, and when your lan is disconnected than I would bet that when you access a file XP(god I hate it) is trying to search your network for that file, or you do have a process running in the background that is taking up mad system resources.
3)Check to see if you are having any memory issues, I have had a system act the way yours is acting before and it turned out that one of the memory modules was failing...usally memory works or it doesnt...so the person that owned it got new memory I installed it and bam, it worked.
4)I know you formated your hd, but if worse comes to worse write 0's to it. I have had 1 case, infact it was my pc, it was doing the EXACT same thing your's is. I did everything I could think of, format, checked my memory, an updated av, defrag...ect, ect. Nothing fixed it, so I wrote zero's to the drive and started working just fine.
Like protege_speed said, its hard to say what to do cause we arn't sitting in front of the pc. I would just make sure that you arn't running any processes in the background, get ad-ware6.0 at
http://www.lavasoftusa.com or get spybot from CNET or TechTv. Scan your system you may find something.
Also, what operating system does your laptop have on it?
