The full PC scan is very necessary for the health of a PC and is highly recommended.
A full PC scan helps in various ways. It is necessary to ensure the following three aspects i.e. the internet protection, the spy ware protection and the mal ware protection. The internet protection implies that you are safe from the reach of the hackers and malicious software that might be sent to you through emails etc. the hackers try to intrude by various ways. They can install malicious soft wares on your PC, by remotely accessing it. The registry ages with time and also gets bigger with use. It gets filled with unused, obsolete and duplicate files. The presence of such files makes the registry stale and it also wastes the otherwise useful memory of the computer. The scan program should indicate if any such files are present in the registry. The scan program should also thoroughly look thoroughly at the different components of the operating system. If an operating system is not being used optimally it too consumes a lot of useful memory and also eats up the CPU cycles, which results in a slow PC. The scan program should also be able to scan the online content, whether it is the text and attachment of an email or the content of a website. Also, It should immediately report if a pop up has a potential threat to the PC security.The full PC scan is always emphasized upon because these days there are many partial PC scan programs available. These scans are popularly known as the protection scans, clean up scans and the tune up scans. Usually they are advertised and marketed in such a way that they promise to indicate all of the problems with the PC. But usually they do not achieve the purpose. Actually many mal wares and Trojan horses are being marketed and sold as the scan and/or fix programs. When they are sold the manufacturer is usually after your money. Their program once downloaded sits in your computer as a good for nothing dormant program. That is why I highly recommend that one should download a free program at least for scanning purposes. Afterwards if anything is found that can not be managed with free fixing software then you can always buy a premium scan and fix program.
So if you are looking for a useful Full PC Scan, try Registry Easy. I am using it at my home and office PCs and it has generated great results.