RAM 8 gig available 3.96 gig what could be the problem?

Question

Iron

Hello.
There was such a problem.
I reinstalled Windows and changed the thermal paste, now I have 3.96 gig instead of 8 gig of RAM.
Windows 7 64-bit
system Pulled out and inserted the percent back (there are no bent contacts).
In msconfig -> boot -> advanced options -> maximum memory writes that the maximum memory is 0, uncheck it and put back 8 gig, apply zero again.
I've tried all the memory settings in the bios, but it didn't help.
I swapped their slats 2 by 4 gig, both workers.
Through cmd I entered commands that I dug up on the Internet - it only got worse).
I already wrote that I have been installing this assembly for 5-6 years on this hardware
aida writes only 4057
In the BIOS I go it says 8
What else could be the problem?

Answer 1

>> What else could be the problem?
In Windows, if you saw 8GB of bios, then it's not a piece of iron
. But anything with Windows .. starting from the fact that it is 32-bit (yes, I saw what you wrote about 64, if Windows is from a tracker, then this happens there) ending with a curve assembly/installation.