You may still have the virus Emma. Your computer isn't just freaking out, it has had its settings changed and unless you did it (unlikely) then it must be a malicious program.
I suggest you run an antivirus scanner, if you have one. If not you can download one of the recommended free ones below.
Two good antivirus programs free for non-commercial home use are Avast!
You should only have one antivirus installed at a time. Having more than one antivirus program installed at once is likely to cause conflicts and may well decrease your overall protection as well as impairing the performance of your PC.
After that read the "Before you post a query" link and then post a query in the Am I Infected
forum for some useful advice and individual help from one of BC's malware experts.