Norton Internet Security 2006 slows my PC

[T.G.]

I have installed Norton Internet Security 2006 on two PCs with windows xp
professional. All updates are installed. My impression is that NIS2006 slows
down the PC substantially, to a degree that is unacceptable

When I try to open NIS 2006 form the program often hangs, the form does not
show its contents, the close button does not work. Ctrl+alt-del is the only
option. If I am lucky I am able to close NIS2006.

NIS2006 insists on scanning an excel workbook when I open it from my local
disk. The scan takes one minute, enough to get me stressed.

One of the PCs hangs when I try to turn it off. I have discovered that I
have to close NIS2006 before I try to close down the PC.

My subscription runs out in 2 weeks. I am not a happy user of NIS2006. The
product seems too complicated with too many bugs. I am behind a router on a
small home office network. I feel I primarily need the virus scan. What is
the best alternative?

Regards

Tore G.