Can not launch PT LE 7.4! Crashes when SETTING UP MIDI

[Ogun04]

Hi;
I had been using PT LE 7.3.1 cs5 until today without any problem. Today, I've downloaded the PT LE version 7.4 and installed it with no error messages and tried to launch it. But everytime I get the same warning when launching, ( it is written "setting up MIDI" on display when error occurs ) and Windows terminated the ProTools application immediately. I couldn't write down the authorization code still Now I've turned back to PT LE 7.3.1 cs5 again.
I've uninstalled and deleted everything before installation of 7.4. The latest version of Inter Lok driver is installed too. WHAT MUST I DO???

Dell Inspiron 6000 laptop, Windows xp sp2, 1.73 GHz centrino, 2 Gb RAM, Mbox2 USB audio interface with updated firmware 1,43.

Ogun.

PS: My computer and PT LE 7.3 were working together successfully.

Here is the error report:

AppName: protoolsle.exe AppVer: 7.4.0.309 ModName: msvcr80.dll
ModVer: 8.0.50727.762 Offset: 0004686a