New
#11
Hello and welcome Mut mate have you tried reseating the RAM and HDD for starters then perhaps run a memtest, you may just have a rogue batch of hardware.
Make a bootable memtest disk set the BIOS to boot form the opto and give it at least six passes - can't do any harm.
Memtest86+ - Advanced Memory Diagnostic Tool
Wouldn't do any harm to run a hard drive test on it either
SeaTools | Seagate > make sure you pick the right bit OS.