There is a problem in installing free AVG 8.0, if your pc has any components of Mcafree laying dormant on installing AVG you will get a problem like avgtdix.sys starting service error 0x80070014 or similar.
This is how i manged to solve the problem:
first you need to completly uninstall McAfee...
1st User account control off
2nd all firewalls off
3rd uninstall Mcafee with
www.mc07.notlong.com (thanks Support 4U) rebot and start
4th uninstall failed components of AVG
http://www.avg.com/download-tools rebot and start
5th next we need to up all temporary files and check for registry issues
i use CCleaner found at
www.ccleaner.com
use both the cleaner and the registry (do several times untill completely clean)
6th Check your hard drive for file/system errors by running chkdsk. Open My Computer and right click on Local Disk C: selecting Properties, click the Tools tab and in the Error Checking area click the "Check now" button and select both options. restart computer ( go have a coffee)
7th folllow with full defrag (have another coffee)
8th repeat step 5 this is necessary!!!
9 Optional* (DO NOT PLAY WITH REGEDIT IF YOU DONT KNOW WHAT YA DOING) check run regedit for McAfee and AVG (should only have the uninstall files and the Legacys)
10 if no active filles of Mcaffe and AVG exist download avg from
free.grisoft.com
11 installed ( or im i just lucky??)
12 dont forget to put ya firewalls and user account controls back on