Unknown problem

My fairly new laptop with Windows 7 Home Premiun had been working perfectly until yesterday things jus seem to be going crazy. At 1st the PC started running generally slow. The next day it started up normally but upon opening Internet Explorer it just froze. I restarted and began running a virus check with my Comodo Antivirus, in the middle of search i saw two error messages saying that Comodo Antivirus and Windows Defender are turned off I should turn them on. I however was unable to turn them on. From that, everytime i turn the PC on, it turns on fine but as soon as i click on something it freezes until long after the screen turns black and i end up having to turn it off using the power button. Right now I am in 'Safe Mode with Networking,' I can't do anythng in Normal startup.
I have no idea wat could be the cause of this, the only thing i can think of that I did was install an update of Internet Explorer to Internet Explorer 8. If I recall correctly, after it had finished installing, i received an error message saying something about 32/64 bit. Mine is a 64 bit OS.
I hope the information provided will be of help in helping me with this prob.

 

sigh..Its very difficult to conduct because i'm only able to use 'Safe Mode With Networking'. I'm trying but my actions are very limited