just installed - problems with network driver :(

i'm having a headache installing parallels on my laptop, it works fine on another comuter with similar software set-up, but it hates my laptop!

first of it failed to install, error message said it failed to install the passtrough driver,
so i re-booted, re-installed - no luck
next i stripped out all the parallels entries from the registry, rebooted and re-installed
it appeared to install just fine,

on starting parallels, it now says "ApiInit: cannot open network driver",
in the laptop's device manager, there is no "parallels host-guest virtual NIC" like on my other PC so i guess the issue is the installer has failed to install the virtual NIC,

i've tried uninstalling and re-installing parallels many times, it always pops up the un-signed driver prompts which i always say "yes" to, but it never installs the host-guest NIC.

how can i fix this? i really want to evaluate this software!