Avast will not accept the license key that I received in an e-mail.
The key is: C1848944H1400A0811-…
Any suggestions?
I am using a Windows 98 system. 
Hi grandmasterb,
Is this a home or pro license?
Where did you get the key?
I am not sure whether it is actually necessary to post the whole key really…
Can you double check the system time and date?
Do these help?
avast! license key tutorial
avast! FAQ >> Invalid License Number
-Scott-
What build of avast! do you have installed?
I have done all of that.
I posted the whole key because AVAST tells me it is invalid and I am hoping that someone call explain WHY it is invalid.
Thank You
i have the Avast! Home Edition 4.7.942
Honestly, I don’t think anybody can tell you what it going on in that ancient version.
I suggest to update to the latest build first.
Well the avast version is way out of date, the current version is 4.8.1351 and that may contribute the problem.
So I would suggest that you do a clean reinstall of the latest version of avast.
Download the latest version of avast http://www.avast.com/eng/download-avast-home.html and save it to your HDD, somewhere you can find it again. Use that when you reinstall. Ensure that you scroll down and select the avast direct download link for the English version and not Cnet as that is for an on-line installation (not what you want to do).
Download the avast! Uninstall Utility, find it here and save it to your HDD.
-
- Now uninstall (using add remove programs, if you can’t do that start from the next step), reboot.- 2. run the avast! Uninstall Utility, reboot. If step 1 failed it may be necessary to run this from safe mode, once complete reboot into normal mode.- 3. install the latest version, reboot.
Hi Guys i too am having this problem and have been for the past 2/3 weeks trying install avast without success. Done all the recommmended thing like check the date settings and still no luck.
Ended up here and deleted/uninstalled all the avast downloads i had on my laptop using David Rs tool just above my post and installed latest version of Avast and still its stillcoming back as invalid licence key
What could be causing this. I am using Firefox and Windows Vista if it helps :‘( :’( 
Desperate
Have you tried getting a new license key (and are we talking about avast 4.8 Home) ?
- Complete the avast! 4 Home Registration form and you will receive an email from register @ avast.com (without the spaces) with your registration key. Use the option I’m a registered user but my key has expired, that should ensure that you don’t get a copy of the same key back.
Are these some of the things you tried ?
Q: My licence key has expired, what to do? http://www.avast.com/eng/faq-registration-license.html#idt_1442
Q: “Invalid license number”. Why? http://www.avast.com/eng/faq-invalid-license-number.html Or Insert Registration Key - Video
DavidR i have tried all the things above from watching the video to see where i am going wrong to checking the date as well as checking if its latest version of avast and in all cases it cheks all the right boxes and yet still keep getting invalid licence. What could be causing this guys as i am at my wits end.
Have unstalled and reinstalled it about 5 times but still same problem
So did you get a new license/registration key ?
e.g. did you check it was a different one.
If you re-register and input the same email that you used before it is possible you would be sent a copy of the one you have (compare the two). That is why I suggested you should use the “I’m a registered user but my key has expired” option.
I know I’m going over old ground but your answer was not detailed, but a I tried everything, call me fickle but I like to know exactly what you have done or I’m guessing.
Yeah they are different keys. Even tried registering with my other email address and was sent different key and yet the problem persists
Please, post the last 300-350 lines of avast log: C:\Program Files\Alwil Software\Avast4\DATA\log\Setup.log
OK, when you did the reinstalls, did you also run the avast uninstall utility ?
If not and there is nothing in the setup.log, a clean reinstall (I know) would be the only other thing I can suggest.
Download the latest version of avast http://www.avast.com/eng/download-avast-home.html and save it to your HDD, somewhere you can find it again. Use that when you reinstall. Ensure that you scroll down and select the avast direct download link for the English version and not Cnet as that is for an on-line installation (not what you want to do). - Direct download for avast Home, English version, http://files.avast.com/iavs4pro/setupeng.exe.
Download the avast! Uninstall Utility, find it here and save it to your HDD.
-
- Now uninstall (using add remove programs, if you can’t do that start from the next step), reboot.- 2. run the avast! Uninstall Utility, reboot. If step 1 failed it may be necessary to run this from safe mode, once complete reboot into normal mode.- 3. install the latest version, reboot.
Ok chaps will try that. So when i do a clean install, do i register for a new licence key or choose the lost my licence key or what
@ Tech, tried to post the log as requested but came back saying the post exceeding the permitted 1000 characters allowed so how do i get around that or can i send PM to you to look at it
You shouldn’t need to re-register, however, choosing a lost key would only send back a copy of the last key, which would presumably have the same problem. I believe there is something hanging around in the registry which may be the problem.
Are you trying to do all this whilst on an account with administrator privileges ?
Before you do anything can you post the first part of the key up to the - dash, e.g. like grandmasterb did in the first post.
Here is the first part of the key
C2764753H1400A0811-
Have also noticed that when try to open the Avast program even to put in the licence key, a box says Wait please, testing operating memory and startup items and this never finishes, like continues to run and you can’t even click on the stop memory button as its not clickable
Have left it to run and 30 mins later and still nothing happens
to insert key, right click avast tray icon > about avast> license key > copy and paste the key > ok.
What do you mean by trying to open avast ?
avast once installed is running, so there should be no need to open anything, other than right click the avast ‘a’ icon, select about avast!. That pop-up window has a License Key button, clicking that will allow you to copy and paste your key into that area.
Pleas describe exactly what you are doing as I haven’t the slightest idea what you are doing ?
There appears to be something wrong with that number as I have just re-registered, clicked the I am an existing user and new a new key; I completed the rest of the form and got a new key, and it looks nothing like the one you posted, this is the first part of mine (W7380058H1400A0811-) and as far as I know the Home version number begins with a W. I entered mine and it was accepted.
What country did you say you were in ?
I don’t know if that makes any difference, but since I’m in the UK and so are you and since there wasn’t that much time between our registrations I would have expected them to have been closer.
Is this the page you visited to register http://www.avast.com/eng/home-registration.php ?
Yes i am in the UK. After i installed avast first time,it asked me to restard the computer which i did and as far as i am aware i should get a little ball/icon on bottom right hand side and i am not even getting that. Therefore the only way i an access avast is running the appl from the desktop
Will try to register and see if makes a difference