R10 random restarts

[dwmet1]

In trying to solve a pesky random restart problem with an R10 DVR I've:

renewed the HDD w/ higher capacity [pre-loaded OS by WeaKnees]
installed an HDD cooling fan assembly
installed a new APC UPS in the power feed
renewed the case fan w/higher capacity
replaced the power supply with known good unit
raised the four corners of the case 3/16" to improve airflow thru the grilles

and the problem still persists from two to five times each day.

The symptom began less than 90 days ago, and to a lesser degree also affects my two other R10's. Is there something else I've missed? The unit was built in 2004 and I've replaced all the moving parts. I can't believe the motherboard, etc., have just "worn out". Something else is amiss. Any guesses?

Thanks for whatever help you can give.

[WK-Michael]

When you put the new HD in the unit, did you copy the OS from the old HD, or was it pre-prepared, from us? If you copied it, you've likely copied a corrupt OS.

[dwmet1]

When you put the new HD in the unit, did you copy the OS from the old HD, or was it pre-prepared, from us? If you copied it, you've likely copied a corrupt OS.I was careful enough to have you do it last month. Should have mentioned that. Thanks for the question.

[WK-Michael]

Sounds good. Was it a new HD?

[dwmet1]

Sounds good. Was it a new HD?Yes. Reference your RO #R250794. It was same make, speed and style but larger capacity than OEM. Which, btw, still works.

The new HD does not seem to be running "hot". I check the airflow temp by hand when an RR occurs and nothing seems amiss. Actually a bit cooler than my Pentium tower or laptop.