I originally had UDK.exe problems a while back (months and months) but it was a patched problem. I did not see any issues for a while, then just recently my PC started doing odd glitchy stuff just before UDK.exe would crash. My video would get jerky, come back, I’d lose the ability to swing my weapon (but console key would work, and so would each key that triggers attacks which didn’t work prior). Eventually UDK.exe crashes again.
I haven’t figured out yet what’s causing my problem, but I think it might be hardware related. I’m doing a reinstall now and I’ll let you know if this fixes my issue, it just doesn’t feel like it’s going to be that easy.
My guesses are dying RAM or a dying power supply (or perhaps too low of wattage, mine is admittedly pretty old). What is the wattage on your PS?