Comodo firewall disappeared -- virus?

Got to the computer today and found that the Comodo firewall tray icon was missing. Rebooted the computer but it was still missing. Tried to start Comodo manually but it was also missing from the start menu. I uninstalled it from control panel then reinstalled and the installation seemed to complete normally. However, after reboot, Comodo was still missing and the installation folder was empty.

I then tried to scan for viruses and found that Avast was also missing from the start menu. However, it's still in the system tray and does run from there. Scanning with Avast, Spybot, Malwarebytes, Superantispyware all came up clean.

I'm concerned there's some malware that's not being detected. The only recent changes I can recall are some minor Windows updates and a Skype update.
Any ideas?

As I've continued to investigate, it now seems like it may be due to disk errors related to several power failures this past week. Thank you to anyone who may have already read my post and given it some thought, but let's put this on hold while I try some things...

Yes, I think it was disk errors. Restored from a recent backup and everything seems fine now.
Sorry for the pointless thread...