GW crashing on start up during file decompression.

Starting 2 days ago, every time I try to launch GW, it connects to Arena net and downloads the new files, but immediately upon decompressing the new files it crashes and I get this error message.

"A serious error has occurred that prevents the program from continuing to run"

In the detail log for the crash it shows the following reason.

*--> Crash <--*
Assertion: Unable to write patch file 'C:\Program Files (x86)\Guild Wars\Gw.tmp'
OsPatch.cpp(311)
App: Gw.exe
ProgramId: 1
Build: 21965
When: 5/29/2007 11:46:38
Flags: 0

I have not changed any hardware or drivers in the last 2 days and this started apparently with no changes on my end. I'm not sure what is causing it but GW will not run. (All other games are still running). I searched the net for GW issues in case it was a network wide problem, but I don't see anyone else having the problem so I'm not sure what is causing it.

Windows Vista Home Premium
Asus A8N-SLI Deluxe (BIOS 1016)
Athlon 64 FX-60
Foxconn GeForce 8800 ONOC GTS 640mb (158.18 drivers)
Soundblaster Audigy 2zs

I'd say go ahead and uninstall guild wars completely and reinstall. Don't save the Gw.dat file.

Ran a repair installation and it resolved the problem, thankfully without a full uninstall and putting 15 CD's in to re-install. (There is a hint NCSoft. Use DVD media for GW2!!!)