AVG caused a boot failure on Kristen's machine this afternoon with a "Causeway error 09: Unrecoverable exception - program terminated" error message which caused Win98 to either hang completely or to run incredibly slowly. Looking on google, causeway is a dos extender program written yonks ago. In the end I booted into safe mode and uninstalled avg.Rebooted and the machine is ok. I'm now downloading Bitdefender which I have mentioned in the past but never got round to using.....until now.
The install was fairly harmless although I did have to download the initial file which was 10mb (a lot more than avg although a LOT less than Norton's 35mb!). It then decided that the pc needed a newer version of MS installer and had to download that. It then told me I needed to reboot (but I said no so I could read the readme file first). Strangely enough at this point it then ran the update program to get the newest definitions and then finished installing the app in the sys tray. I was, at this point, able to save a copy of eicar.com onto the desktop which was a bit worrying - BUT I'm giving it the benefit of the doubt as at this point I had not rebooted.
A quick reboot later and it reckons the laptop has 4 virus's on it (two of which were my copies of eicar) which is a bit worrying as this machine has had Norton on it for over a year (with weekly scans) and AVG on it (with no detections) and the files it has picked up are really old ones so I think they may be false positives (but I'm deleteing them just in case)
It looks like you can't put the memory resident shield on until a full scan has been done (or at least I hope that is the case and they haven't crippled the software so that you have to purchase it to get the memory resident scanner)
You get what you pay for...