NEVER click on a link unless you are sure its safe!
Clicking on a link can expose your computer to infection - and expose you to all kinds of scams. You should always check out a link to see if its safe. HOW?
HMRC Tax Returns Online <- this is a link
Rest your mouse cursor over the link above - DONT CLICK! This is called hovering. At the bottom of your browser screen you will see some text telling you where the link will take you. Notice that the text does NOT say "HMRC etc" or anything remotely similar. This is a clue that the link may not be safe.
Try hovering over this link - would it be safe to click? Answer at bottom of page.
Links - especially in emails - can take you to an information harvesting page that aims to steal your identity. Here is an example copied from a scam email, but made safe, and with corporate graphics removed (so I don't get prosecuted by AMAZON). The email claimed a payment had been refused
Installing programs can be even more hazardous, and you should only do so if you know the program is clean (such as the programs listed on my site here).
When browsing you may find a window something like this appearing on your screen
The above is an example of a fake "spoof" program that pretends to find and remove infections. It WONT - it will put them on!
How about this - Optimum PC Boost (or similar) - it HAS to be a good idea to speed up your PC?
No, NOT a good idea. More than likely it will open up your PC to all kinds of malware, and may even turn off all your virus protection. Other fakes will claim to improve the stability of your PC, keep your drivers up to date, etc. NEVER - NEVER install these programs.
ANY PART of an image or browser window can be a link. So if you click "Pause" "Stop" even the big red X - YOU WILL INSTALL UNWANTED PROGRAMS - and MAYBE some real nasty viruses. If you see a screen similar to this when browsing, the ONLY safe thing to do is CLOSE YOUR BROWSER.
And the safest way to do this is
Right click in the taskbar (bottom of your screen); select "Start task manager";
Right click on the entry for the browser you are using; and choose "end task".
Answer: you will have seen the link is identified as http://www.lloydsbank.com/ - so its safe. A link on an email from lloyds bank might look like that. If it looked something like this (below) it would NOT be safe.
Nor would this one - on an email "from HMRevenue & Customs"