the laptop is buggered, sometimes text doesn't load, sometimes it shuts off the internet connection and refuses to find any wifi connections. I think the last repair guys messed up some software because at the All Control Panel Items > System, at the system bullet point it shows the logo of that repair shop and its contacts instead of ASUS'
Im not very experienced in this so any help and suggestions would be very much appreciated
That ASUS writeup looks great. I would add a couple of things:
I've had better luck when I chose the "remove my files option" like is shown in the writeup. It does what it says so make sure you have backups of your data. Now is a good time to reorganize and delete stuff you no longer need.
Also, if you run BelArc Advisor and save the output, you will have a list of most of your installed software and any associated keys (I have seen it miss a few things).
Make sure you do the Windows Updates (in Setup/Updates and Security). You will have to do this repeatedly to get all the updates. Now run the MS cleaner (right click on C drive, click properties and select Disk Cleanup and then select System Files. Enable all the check boxes and run that. It will free up a large amount of space.
Now reinstall your programs and copy your data back from the backup.