Pl identify exact Win 7 version - supported versions are listed in the Install Guide - Oracle&reg; Database Express Edition
Assuming you are using a supported version, pl review the install log (see Step 12 at Oracle&reg; Database Express Edition) and post any erros here
the win 7 version is listed in the guid (win 7 enterprise)
After the wizard installation i haven't a log file in the windows directory. I search the complete c disc and did'nt find this log.
log file after silent mode:
setup.exe /s /f1"C:\Program Files\oracle_install\OracleXE-install.iss" /f2"C:\Program Files\oracle_install\OracleXE-install.log"
Pl do not use directories with any spaces in them (e.g. "Program Files") when installing Oracle software - try directories without spaces.