Minidumps - PC acting wierd/freezes in BIOS

[tweaks_sav]

This PC is acting really wierd. It seems to work fine for a few weeks or so, then starts cyclic booting, BSOD, or just stops/freezes with no errors. Event viewer seems clean. Memtest and HD test both pass repeatedly. Any help? Thanks.
I think it may be the mobo or CPU.
Mini031307-01.dmp is the most recent and has lots of info.

Zipped minidumps attached.

 

[cpc2004]

It is hardware problem and it is internal timer problem.

Mini020807-01.dmp BugCheck 9C, {0, 8054d370, a2000000, 84010400}

Refer the following problems and the symptom is same as yours
https://www.techspot.com/vb/topic39639.html
https://www.techspot.com/vb/topic36391.html