How do I repair and reinstall online protection when the software can't do it by itself?

I have online protection however software problems stop it from updating. I have tried to reinstall but it fails. During the anti-virus scan it freezes and I have to reboot. I have erroneous programs on my system but are unable to remove (control panel). I have tried everything I know but I fail at every turn. My system is so sluggish that it is a chore just to navigate. I want to put a bullet into it. PLEASE HELP!!!!!!!!!!!!!!!!!!!!!!!

How do I repair and reinstall online protection when the software can't do it by itself?antispyware

Try booting into safe mode and running your antivirus again. You may also want to install, check for updates and run the following antispyware applications, also in safe mode. To get to safe mode, tap or hold down the F8 key while the computer starts back up. After a few seconds a screen should appear to allow you to select safe mode. To exit safe mode, simply reboot again afterwards.

SuperAntispyware

http://superantispyware.com/

Spybot S%26D (free version requires manual updating)

http://www.safer-networking.org/en/downl...

AVG AntiSpyware

http://free.grisoft.com/doc/20/lng/us/tp...

Adaware from Lavasoft (free version requires automatic updating)

http://www.lavasoftusa.com/products/ad-a...

(These programs can be run in Safe Mode after downloading and updating)