Yes, assuming that you have the full package SP2 installer, you can launch it in Safe Mode and will complete there. At the end, you'll be asking to restart.
If some drivers are incompatible with Windows XP SP2 after the installation, you might encounter some problems.
Q873161 -"After you install Windows XP Service Pack 2, your computer restarts"
Q870892 -"Your computer repeatedly restarts, or it generates error messages when you roll back two or more device drivers"
Trying to unweave, unwind, unravel
And piece together the past and the future,
T. S. Eliot
I keep getting this on my XP Pro machine when I apply the SP2. The installer then aborts. I have tried with and without AV software running. I have made sure there is no spyware running... Adaware, Spybot S&D, etc. Any ideas? maybe a safe mode install?