^ Don't run CINE more than 2 times in a single session, always restart as score starts dropping. BTW, if you're changing BCLK in Windows do it with Cine closed as it internally defines how long 1 second is using QPC.
In 2.25 if you selected, say core 6, it actually selected multiple cores (I think 3+4 or something like that), so now your previous experience has changed. I just run with all cores but first, seems to score the highest.
You didn't lose cpu points. In previous versions it seems that GPU/CPU scores were mixed so the final score displayed was miscalculated.
Take this random example:
v2.25
GFX = 430 * 100 = 43.000 pts
CPU = 550 * 50 = 27.500 pts
v2.26
GFX = 550 * 100 = 55.500 pts
CPU = 430 * 50 = 21.500 pts
EDIT: the final 'triscore' was not affected as it's not calculated but directly retrieved from Aqua.
For what is worth, you should now actually score higher as the cpu affinity was fixed too.
The CPU is there, but I think it has to do with DJ not being able to submit in the respective category, I know he has been trying for the last couple of weeks.
EDIT: moved them to V2, let me know if there are others.
There are other parts involved in the process and the battery may not be at fault. You can either try another battery from a friend / IT workshop or just send the netbook in for repairs.