As a general rule, anything system restore can do a aystsme image can do better. With a system image, then except in the extremely unlikely case of a firmware infection, you will certainly wipenout any viruses, you will alos undo any damamage to system files, and revert all settings to those at the time the image was made. After fixing the computer you should make a system image as soon as you have it in a clean non-infected state with the programs you use installed, the settings you like set and a working antivirus in place. If a system image is made at a time when a system is clean and working nicely then it is also better than a factory image, because with a factory image you have to reinstall all your programs and reset all your settings as you like them.
A system image MIGHT wipe out personal files or it might not when you restore from it, it depends how your drives are partitioned, if the partitioning has personal files on D:\ and windows system files and program files on C:\ then you can make an image of just C:\ and the couple of hidden windows system partitions and when you restore from this image files on D:\ won't be overwritten.
Personal files should always be backed up on external media just in case.
System images should be kept on external media.
To add three extra tips, along with those provided by TsVk! in post #4, for keeping secure in future I also advise:
1. backup all your personal files regularly, every document, image, video file, audio file, zip archive... should be stored on atleast two external devices as well as on the computer. Ideally you should have an offsite (uploaded as an attachemnt to a webmail account, stored in a cloud backup service, on a USB or CD at the house of a trusted friend or relative) backup also.
2. backup your system status using a system image, here is how http://www.bleepingcomputer.com/tutorials/create-system-image-in-windows-7-8/#manual
. Do this on a clean system once when it is brand new, then twice when you have your programs installed and all your settings as you like them. Do this before any browsing on the internet, and before starting to fill up the hard-drive with large personal files. In total this requires 3 external devices, each atleast 50GB in size (precisely how big depends on how many programs you use, 50GB is the minimum for someone who doesn't have that many programs). If you ever have an emergency in future you can restore from the image, then copy your personal files back into place( you backed them up under suggestion 1.), then just update your programs, your browsers, your antivirus and any windows updates you need and you are back as you were before the problem began, within 3 or 4 hours maximum.
3. run a script blocker in your browser, NoScript in firefox is good, and run an anti-exploit program, malwarebytes anti exploit is good. Both of these, the examples I give will happily run together on the same machine providing two defensive layers on-top of your antivirus, help prevent drve-by infections, which is one of the scariest ways a user can get infected (just visit a page and instantly you've had a plugin, or the browser itself, exploited and you've got a virus). Careful browsing is helpful, but because malvertising adverts can appear on reputable sites it isn't enough alone, you need to take action to block drive-bys from being ble to run.
Edited by rp88, 23 July 2015 - 05:09 PM.
Back on this site, for a while anyway, been so busy the last year.
My systems:2 laptops, intel i3 processors, windows 8.1 installed on the hard-drive and linux mint 17.3 MATE installed to USB