Avast disappoints

[Akash1]

When i installed avast on my mom's new laptop (win8), it wasn't able to boot immediately after the next restart and had to be formatted. I never had this trouble before. I am sure that nothing conflicted with it.
Also i my pc (win7), avast caused a lot of driver problems (modules showed up but didn't load) and made my net unusable.
the next moment when avast was removed, my pc came back to normal. Please guide.
Thanking you
Akash Ravi

[Pondus]

what antivirus was installed before installing avast?
did you uninstall it before installing avast?
did you use the vendors removal tool to clear any leftover files that may conflict?

[Kamika]

If windows 8 still has safe mode then you could have booted into safe mode, uninstall avast using the Avast cleanup tool and win 8 would boot normally again. You should only use a reformat as a last resort. We're sorry that your first impression of Avast was a bad one.

[RejZoR]

When i installed avast on my mom's new laptop (win8), it wasn't able to boot immediately after the next restart and had to be formatted. I never had this trouble before. I am sure that nothing conflicted with it.
Also i my pc (win7), avast caused a lot of driver problems (modules showed up but didn't load) and made my net unusable.
the next moment when avast was removed, my pc came back to normal. Please guide.
Thanking you
Akash Ravi

So, you have upgraded Win7 directly to Win8 ? Are you sure you weren't using an outdated version of avast! that wasn't compatible with Win8 ?

[true indian]

Confirming a bug on Win XP 64b - none of 32b apps will start because of Behavioral shield. Turn it off or wait for fix, please.
It's so rare os that we skipped it in the latest testing rounds to save a time... And a new bug appeared. We are sorry for inconvenience

Lukas.

Lukas,didnt mention anything for Win8 or Win7...so without any adequate explanation..we cannot help you akash

[Akash1]

Please make note that it was a brand new lenovo just upgraded to win 8. avast was my first 3rd party soft. The very latest version which said win 8 compatible. Moreover when the booting failed, it took me to a recovery console. Auto repair couldn't solve it. Being a experienced user, i tried to remove it to my best using cmd. But no luck.

[Pondus]

did your lenovo come with a preinstalled antivirus?
if so did you remove it before installing avast?

Being a experienced user, i tried to remove it to my best using cmd. But no luck.

read and follow instructions
Uninstall Utility. http://www.avast.com/uninstall-utility