Antivirus softwares

To all those who are not very proficient in IT stuff,

I have been having quite a headache with my laptop these 2 years.
Can't find a suitable antivirus for it. I used to use avast but it's causing my laptop to shut down autmatically after some time., in the middle of my work, and without any warnings.
So JY recommended jy's blog. Ya, and so the following are some of the softwares that jy recommended.
Useful softwares:

avast! antivirus...www.avast.com (jy use this one... good and easy to use)
AVG...www.grisoft.com (both of our brothers use this... and they have a spyware removal too! JY's bro highly recommend AVG)
Spybot...www.spybot.com (spyware remover that is free.. easy to use.. average grade)
Lavasoft... www.lavasoft.com (adware remover.. easy to use too)
Trendmicro housecall... www.trendmicro.com (available free online virus scan. but limited capability in deleting/repairing the virus)
for more program can search from www.download.com alot of things there.

Special thanks to jy and of course JY for introducing me to jy's blog.