WAMP5: after successful install, it wouldn't start (stays in yellow)

Hello Experts,

I have Win7 machine 64 bits.... I just tried to install

wampserver2.2e-php5.4.3-httpd2.2.22-mysql5.5.24-32b
and
wampserver2.2e-php5.4.3-httpd2.2.22-mysql5.5.24-x64

both install successfully but start fails (it stays yellow)... localhost wouldn't come up... I attempted to restart services several times... nothing..

FYI... I did install previously Visual C++ 2010 SP1 Redistributable Package x86 or x64

any ideas?

Regards,