Lewis wrote:

<<I ran Norton anti-virus scan and it detected four Trojan virus' but was
 > able to fix them. The report said "Quarantine failed". That worried me
 > very much>>

I missed the original posting because of your meaningless subject
heading---which I've taken the liberty of re-phrasing.

Letters posted with irrelevant headings may easily get overlooked.

I assume you mean "unable to fix them".

It's likely that these viruses are in your System Restore folders.  Many
a-v programs can detect them, but because all Restore files are protected,
they cannot be touched. Therefore you will get the report that they cannot
be quarantined or cleaned.

The only remedy, if that is the case, is to disable System Restore for each
drive. Be warned that if you do that, you will lose all Restore
Points.  Which you wouldn't want anyway, if they are infected.

If you know what you are doing, you might be able to delete selected recent
RP folders, while preserving earlier ones.  That might be a better
solution, but you'll need to do a bit of detective work to reconcile dates
and which points are full restores and which are merely updates. But it can
be done.  But there's no way of telling when your computer first became
infected, unless you run regular full scans.

Don Penlington
 From the Beach at Surfers Paradise in sunny Queensland.
Computer tutorials, local scenery,  and other things at my website:
http://users.tpg.com.au/deepend/index1.html