Your glibc seems ok (a bit outdated, but not critical)

> 4. MemTotal: 7911216 kB (8 GB)

  I mean - could you run memory test to ensure your RAM is ok ?
Random corruptions of different databases could be sign of hardware problem (not necessary, but
possible)

> 5. Here is a part of my less /proc/cpuinfo - Is it weird that I have 4 GHz but the cpu MHz just 800 Mhz ?

  It is OK, while CPU is not 100% buzy

Regards,
Vlad