A full PC scan is very necessary to ensure the health of a PC. It has several components and each one is equally important.
The full PC scan program keeps the computer miraculously secure. It achieves this purpose by indicating the entire troubles one after the other with your PC. Then it is the duty of the repair program to fix all those problems. There is a whole range of problems that only a full PC scan program can indicate. For example the PC scan program should scan the whole of your PC registry. 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. The clean up and the tune up scans are responsible to protect and up keep the health of the PC and the operating system. These scans look for obsolete files and duplicated files to delete them. This in turns frees memory space and the speed of the computer system is improved. So actually if we run a protection scan, clean up scan and the tune up scan simultaneously, it will be called a full PC scan.
The full PC scan should also ensure the spy ware and the mal ware protection. The purpose of the spy ware is, as the name suggests, keeping a check on your activities. It does not matter if you are online or offline; the spy ware software will record each of your activity. An example of the spy ware is the Key Logger software. 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.
If you want to perform a Full PC Scan, try Registry Easy. It has miraculously helped me solve all of my PC problems.