serious problems after routeine memory upgrade

I recently did a memory upgrade on this device. After the upgrade was complete I noticed some strange problems that I could not explain. First some of the keys on the integrated keyboard did not work. I did a battery reset and it seemed to correct it but the problem soon returned. Further attempts to reset the battery produced no results. Then I noticed that the computer would no longer operate on battery without the charger. The OS claimed the battery is charging but stays at 87% and the computer dies immediately when the plug is pulled. Furthermore I am now noticing problems with the headphone jack. This all happened within a few days of the memory upgrade despite consistent fine operation for years.