well... you didnt say anything about cpu usage, but i would say if the cpu usage is abnormally high (which could also cause things to take much longer to load), that he could have contracted a virus of sorts (even within a day)...
it could be a driver conflict of sorts too, or a subpar driver even... try running scandisk... but, if the raptor doesnt show up with any problems in eventviewer or with scandisk, then i would begin looking elsewhere for causes to this.
Run a full drive self test to see if the hard drive is healthy. Someone in shipping could have used it for football practice!
Close down anything accessing the drive and run HDTach and report the speeds.
If the drive is health and HDTach shows its working fast then the slowdown is likely software related.
I would also run Adaware and Spybot to check for spyware which normally doesn't show up in virus scans.
I am also assuming you scanned for viruses (if not I suggest Avast 4 Home).
I am also assuming that before you connected to the internet you applied all the latest security updates and turned on a firewall. (Autopatcher XP is released monthly and has all the post SP2 updates up to its release).
Its nearly impossible to update a pre SP1 system via the internet before it gets infected.
SP2 with Windows Firewall enabled will probably last long enough, but I always Autopatch first just to be sure.