Help Please ?

Lizzie asked me to sort out her lappy,so turned it on and knew straight away it had a virus

It was blocking all internet access,wouldn't let me into the anti virus etc etc......

Anyway I did a system restore and eventually managed to get internet access, and download malwarebytes sucessfully.

I have run it 3 times,first time it picked up 60 infected files
Second time it has picked up 25 infected files and third time it has no infected files,it has 71 quarantined files all infected
My question is can I delete them or do I need to keep them in quarantine ?

Do a backup of all your documents/photos etc. then delete the quarantined files.

Then, have a look at k9paw's thread called 'virus?'. I posted some info about computer security in there. Personally, if I were running a system that was vulnerable to viruses and I got hit by ~150 infected files I'd be looking seriously at migrating to a more secure system! As it is, I use a more secure system very successfully. I am quite sure that if I installed* and ran anti malware software right now I'd have 0 infected files. Even if I did find some, I wouldn't be worried because I know they couldn't actually execute and do anything.

*Note, I'd have to install AV software before I ran it because I don't have any installed on this laptop at the moment.

had the exact same thing last night..with my sons laptop..I reformatted it!!

The thing is that reformatting and carrying on seems to be treated casually. Bearing in mind malware these days is used for criminal activity rather than just annoying pranks, I personally think infected files should be treated as if someone had tried to break in to your home! If that happened, you'd do things like change locks...