Most users wish to surf the internet and this requires that security software is installed, there are many products offered at varying prices, but unless your Internet Service Provider or Internet Bank offer free software would not be lured by the power of advertising.  Microsoft Security Essentials is highly recommended.

Please note that Microsoft are currently rolling out Office Genuine Advantage to check validity of your Word, Excel, Powerpoint, Publisher etal.  If you have a Pirated copy installed would advise to uninstall and install the Freeware Open Office which has good compatibility with Microsoft Office:

http://www.microsoft.com/genuine/downloads/FAQ.aspx

Wherever feasible I install the following freeware software, which are all highly recommended for both Windows Vista and Windows 7:

MS Security Essentials  http://www.microsoft.com/Security_Essentials/default.aspx

 

Malwarebytes Anti-Malware Scanner  http://www.malwarebytes.org

 

Microsoft On-line Safety Scanner  http://onecare.live.com/site/en-gb/center/whatsnew.htm

 

Email SpamFighter (Outlook 2003 and later & Windows Mail) http://www.spamfighter.com

 

VLC DVD Player  http://www.videolan.org

 

Open Ofice Office Suite http://www.openoffice.org

Windows Vista includes Windows Mail, Movie Maker and Photo Gallery.  Windows 7 has none of these programs, they have been replaced by Live Mail, Live Movie Maker and Live Photo Gallery available via Live Essentials 2011 which is also available for Vista:

http://explore.live.com/windows-live-essentials?os=other