Thank you all for your follow-up and sharing. Ok, fair enogh, my problem statement could be clearer.
It's a UMPC, here's the spec: 1GB Ram, 16GB HD, Intel Celeron for CPU at 900Mhz.
Use case: it's a software demo platform for me (and intended to be used in a simlar fashion for users as well), I can almost eliminate its need to get on the net. Got some sort of malware a few days ago, which slightly messed up my presentation the other day (later used another trusted program to diagnose the problem and fixed it and heard good thing about Avast, hence, installed it as an extra help, and ran it for scanning, found 0 problem, good thing). And since I intend not to use this UMPC for any internet activity again. The net protection is not required. But I don't want to remove/uninstall it for now, just in case ...