Could we install free home version antivirus programs in our laptops?

Of Course You Can! Yes, Affirmative.

Could we install free home version antivirus programs in our laptops?vista

I have used AVG Anti Virus, Zone Alarm Firewall, Spy-bot Search and Destroy and Ad Aware both spyware killers for years. They are all free for personal use and I have had no trouble with Viruses Trojans etc. AVG does not slow the system down as much as some other products and Zone Alarm allows a lot of personal configuration unlike the Windows Firewall. They can all be downloaded from the following linkhttp://www.computeractive.co.uk/. On the home page select downloads and then the appropriate category.I also use Windows Defender from the Microsoft site. It is safe to use two anti-spy products but never use more than one A/V as it can cause conflicts. You should run A/V and anti spy weekly. Hope this helps

Could we install free home version antivirus programs in our laptops?antispyware

yes
Yes - AVG is really good but won't help you if you already have a virus. See the website below.
Of course. If you are a company, and your laptops are official company use laptops, the free AV software might have stipulations that prohibit such use without purchasing licenses.