It's always helpful if you can provide us with the Make/Model of the computer you are having this issue on. Also, is it a Desktop PC or a laptop. Next, if you want more detailed help, please download the free SPECCY program from piriform.com and post back text result file here for us to analyze.
Have you tried making a complete backup of your Personal Data to external media and running SYSTEM RESTORE prior to the firewall problem occurring? You may have contracted a nasty virus or windows system corruption (assuming your hard drive didn't crash).