Laptop - won't boot into safe more or boot from CD

[Smasher]

Good news - connected HDD via magic bridge for a virus check & clean and it's now booting again in laptop.

Bad news - Avast antivirus won't run (and neither will upgrade to 5.0) due to a 'software restriction rule':

Access to C:\Program Files\Alwil Software\Avast5\AvastUI.exe has been restricted by your Administrator by location with policy rule {8aecd3ec-dc47-40ca-b645-0d18e64daccc} placed on path C:\Program Files\Alwil Software

Any ideas on how to lift the 'restriction'? Can only assume this is a result of the virus/malware.

[Smasher]

The laptop even refused to boot off a CD so simply formatted HDD and carried out a fresh install. All working fine now. Thanks very much for all the help and advice, much appreciated. It appears whatever the virus/malware was it knocked out Avast Antivirus, prevented CD boots and eventually stopped it booting up at all.

[CWH]

Glad you - finally - got it fixed.
Do you have any indication of how it might have initially started?

Colin

[Smasher]

I was using a 3G mobile (tethered) and disabled all updates so the allowance didn't get eaten up. I can only assume that's how the trojans and other malware found their way on, although it seems there was some kind of block stopping Avast from running in the first place. Won't know for sure but at least I know next time I'm on 3G to re-enable updates straight away.