NIS2010 Freeze PC, but NIS2009 Does NOT!

After installing NIS2010, PC freeze under two senario:

 

1) PC idle for 10-20 min with or without screensaver

2) PC runs while NIS starts background scan

 

But NIS2009 works without any problem.

My laptop's configuration seems to fit into the NIS2010 system requirement:

 

Microsoft Windows Vista® (32-bit) Starter/Home Basic

Compaq Presario C700 Note Book PC
Intel Pentium DualCPU1.73GHz T2370
2.0GB of RAM
106 GB FREE hard disk space