When should more memory be added to a computer?Can the same antivirus software be used on laptop and

Memory-

More is generally better, but there can be economic factors as well. If you need to improve performance on an old computer, this is the best way.

Anti-virus-

I assume that you mean you have purchased one copy. It is generally not legal to use on more than one computer. The very best antivirus programs are free though-

Spy-ware, etc: Ewido.com, ad-aware (www.lavasoft.com), spybot search and destroy (www.security.kolla.de) Google a websearch specific toolbar too.

Anti-virus, there are two free ones that are superior: www.grisoft.com has AVG, and www.free-av.com has avira anti-vir. You can only run ONE anti virus at a time, but can run multiple spywares. Download and install these programs, and boot your computer to safe mode (hit f8 on a re-start BEFORE windows comes up). Run them from safe mode. Good luck.

When should more memory be added to a computer?Can the same antivirus software be used on laptop and desktop?computer security

First question: When your computer begins to take a long time running applications, when it freezes often.. I say if you check your current memory (Right click My Computer and go to Properties) and it is less than 512MB, you need to upgrade.

Second question: Yes. Just copy the setup file to your second computer. Or, install using the disk. You can use the same serial number for a limited amount of times I believe, but it can be done.