I recently noticed my battery light blinking amber nonstop. I did the hard reset and it seems to have worked for now. However, I still believe this battery is about at the end of its life cycle (it's about 5yrs. old), so I wish to invest in a new one. The numbers on my present battery are #PA5109U-1BRS. The #s under that are PABAS272. I've been all over the net looking and can find batteries with the 1st. set of numbers, but there aren't the #PABAS272...lots of PABAS#s, but not my 272! How important is this second # ? Help! Need to get a new battery before this one dies of old age. FYI...neither Toshiba nor Dynabook (who took over my model) even sells replacement batteries for my machine. Thanks in advance.