"Your computer is being monitored" "keyloggers" and "your system has been hijacked" ANY ADVICE?

Last night my windows security centre started going crazy, it disallowed my firefox and telling me that my PC was infected and suggested it's antivirus software (for me to buy it), notifcations every 30 seconds saying "Your computer has been hijacked" "your computer is being monitored.. by third party" and "keyloggers and other tracking (devices) may be in use)" I panicked and system restored to three days ago. Since then everything has been fine, I googled the it and it looks like it could have been BOGUS theats, by a virus. Do you think there's a chance that the threats were authentic?