Hello RKinner, it's missmoody here now. My boyfriend who was helping was desperate to go to bed, so I said I could manage to finish the rest.
I've now done the following: deleted the FRST quarantine folder; checked that Flash is up to date (it is, and is currently disabled); disabled javascript in Nitro Pro (PDF reader); installed Ublock Origin; changed the punycode 'thing' (very technical term) in Firefox and tested it; installed FB Purity; installed CryptoPrevent.
I'm switching to a different ISP on Wednesday and getting a new router, so will heed the information regarding the password and encryption when it's set up.
I've been getting notifications about updating Java for the past couple of days, but haven't done it yet because of the issues I've been having, so I will sort that out tomorrow.
Other than deleting folders and logs for any tools we've used (which can also wait until tomorrow), I think that's everything.
Thank you very much for your help - it's greatly appreciated.