If all you do is surf and read email, then you'll probably be fine with Ubuntu.
It's free (or nearly so), and you can easily try it out by booting from it's live CD.
It can be installed over the existing OS,
or on it's own disk partition (so either OS can be booted).
Prior to committing to a new OS,
you should first assure that it supports your peripherals (printers, etc).
And prior to installing a new OS,
you should backup any/all files of interest (e.g. documents, email addresses, bookmarks, etc).
You use Windows, but fail to keep it updated
Many Windows updates address recently-discovered security vulnerabilities.
And once these are made public, hackers quickly develop & issue attacks
that exploit these vulnerabilities.
Solution: Enable Windows Automatic Update (so as to get updates ASAP).
You use Internet Explorer instead of any other browser
I.E. (like Windows) is the preferred target of hackers (as it's used by the most people).
Solution: Use FireFox or Chrome (preferrably with the "NoScript" or "ScriptSafe" add-on - see below).
You view a web page that contains a virus
Web pages normally contain text, formatting info, and images (static stuff).
But they may also contain little programs (or scripts) written in languages like
And it's these scripts that can infect your computer (if your browser allows them to run).
Some are within ads, so even legitimate sites can unknowingly host these viruses.
Do NOT use Internet Explorer (the preferred target of hackers, as it's used by the most people).
Instead, use FireFox with NoScript, or
Chrome with ScriptSafe.
NoScript/ScriptSafe block all scripts/programs unless you specifically enable them for that site.
But don't forget that it's installed, lest you'll get confused/aggravated when a web page does not look or behave
as expected. Click the add-on's icon to enable scripts as needed.
You run a program that installs a virus
Download programs only from reputable sites.
When you click a link to a program that you wish to run, select "download" (NOT "run").
Then scan the downloaded file with an anti-virus program
Windows Security Essentials,
If it's an installer, also scan the installed directory prior to running the installed program.
If a web site ever prompts you to install "required" software or an update to same
(e.g. "this site requires a flash update"),
do NOT click the link to install it (it could be a fake link to an "update" which is actually a virus !).
If you think the update request might be legitimate,
then Google the product name to find the vendor's actual site.
Then install it from there.
You click that email attachment (from a "friend")
Attachments can contain viruses.
And if your friend's PC is infected, it can send emails on it's own.
So do NOT assume that your friend actually sent it.
Do NOT use Microsoft Outlook (the preferred target of hackers, as it's used by the most people).
Instead, use Thunderbird or a web site for email.
Move the mouse over the link in the email.
A status line (near the bottom of the window) should then display the real link (vs its description).
If the file name ends with is .JPG, .JPEG, or .TXT, then it's safe to click.
Else, do NOT click it until you verify with the sender.
Scan the attachment with an anti-virus program.
btw, most AV programs do this automatically when your email is downloaded.
You view your email messages with HTML formatting
HTML (the formatting language used for web pages) can contain scripts that load viruses
If you read emails with your browser, see #3 above.
If you use an email reader, set it up to display emails in simple-html or plain-text (in Thunderbird, click View / Message Body As / Simple HTML).
We welcome any suggestions/criticisms re this information.