XP wont allow install of AV software?

I got a laptop from my Father..its an HP Pavilion zt 1145 a little old but in excellent condition..I cleaned everything up and can get on the internet..I downloaded some AV software from Alil (Avast Home) I click to install and I can get to the page where it starts to install but then it disappears and is nowhere to be found..seems like something is shutting it down or blocking it..I'd prefer not to browse the net without some sort of AV software..any ideas or help would be appreciated..Thanks.


John

 

Did alittle investigating and found errors...all seem the same...Service Control Manager
The Application service terminated with the following error: The specified Module could not be found.

I downloaded the AV exe file to My Documents and then went to install.

hope this info helps.

John