Please help me fix this...

n I am working with an hp pavilion amd turio 64 x2. I just bought the
computer a couple of weeks ago. I had trend micro anti-virus and webroot
spysweeper installed at the store. Now my computer keeps giving me the
multiple security problems alert. It says malware protection, and windows
defender is turned off. When I click to turn defender on, it gives me the
same message as pretty much everybody else here. Searching for
definitions-and then windows can't find definitions at this time, etc. I
can't turn defender back on, and I'm paranoid, beacause it keeps giving me
the alert-its red. I click on the find a program beside the virus alert and
it takes me to a software page with symantec, trend micro, etc that I'm
supposed to buy. It says the firewall is intact and the spysweeper, but I
can't do a thing about the virus ware, and defender. I went and downloaded a
free trial of the 2007 trend micro and it still says its not found installed
on the computer, but at least the icon is at the bottom of the screen now.
Does anyone else have this problem, please help, if you find out the answer
my email is c_robinson84@yahoo.com. Thanks.