Entry point not found?

I use the free version of avast in Windows 7. I installed latest updates and now I can’t even open avast. The error message I get is
Entry point not found… The procedure entry point blah could not be located in the dynamic link library blah.
I get this every time I try to start avast.
Do you reckon it didn’t install updates properly? Should I uninstall every bit of it and then reinstall the latest version, or is there something else I can try?

unless someone here have a better idea, i would try reinstall yes

read the instructions - remove with this http://www.avast.com/uninstall-utility

Thank you. Should I definitely use this to uninstall or can I try via control panel first? Ta.

you can do ad/remove first