Ok so its been a frustrating week or so trying to make UDK run.
I've already uninstalled and reinstalled stuff, UDK(Nov 2011 version and the Jan 2012),net framework,ati drivers..

It was working fine before(NOV 2011 version) I installed it tried it and for a while didn't use it.Between the time it was last working and now that its crashing I updated my ati graphic drivers twice.

At first its crashing on startup and it won't load up even the welcome message and the content browser,it just crashes.Then I tried re downloading and reinstalling stuff(I have JAN 2012 version now) and now it starts up but once I closes the welcome message tab or try to press import from the content browser is just freezes then crashes.

This is the first time I had problem running UDK on my computer so I really have no idea what went wrong,I'd appreciate it if anyone can help me sort it out.

Check your event viewer > application logs, might be able to get some more info. Hard to suggest much more.

Uninstalling can leave residual files, if you try to reinstall again be sure to manually hunt down everything and delete it by force.