To all: don't reply to my post. I know this is an old post, but I had the same freeze issue in ABAP trial NW 7.31; it was the first time I was going through the web gui after the installation; after the login, the freeze happened just at the moment of the splash screen, although it was not displayed (image not found). I corrected as follows.
I applied the tips from Paramvirsinh Jetawat (there is also a note 1651937 about same topic) but it didn't change anything (at least I couldn't see if it had changed anything).
Then I saw that the ITS services were partially published (especially the splash screen in the SYSTEM its service), so I activated the whole ITS service (SE80), and it was okay.
I later saw that it's a recurrent problem with ITS services: http://scn.sap.com/community/abap/blog/2012/03/26/configure-web-gui-for-sap-netweaver-701-sr1-sp3-abap-trial-version