You should answer any questions previously asked.
You should follow any previous suggestions given and report the results.
I don't think your problem is the same, based on what you have said about avast about to expire and what you have done.
Reinstalling avast won't get round the fact that it will expire soon as the original registration key you were sent is valid for 14 months of updates. You need to reregister and you will be sent a new key.
Sorry, I thought it was enough to answer if I had other anti-virus or firewall...
I don't have other anti-virus and I named the other things I have on my computer...
I didn't know before that if avast was to expire I didn't need to reinstall it, just change the key. I didn't know it because it wasn't me that installed the anti-virus before.
But I have done both: I uninstalled avast, then I installed it again AND changed the key.
After that the resident protection didn't work. So I reinstalled it again cause I thought it could be some damaged file. I repaired it. But it didn't work either.