When you upgrade RAM on any computer, not just laptop, the first time that you turn the computer on, it may display some information about a change that you just made to the configuration. This is normal behavior, it just means that your computer is adjusting to a change that you made to the hardware of the computer and, because of that, it is essentially updating the configuration to allow the extra 4GB memory module that you installed to take effect and give the boost that you wanted. It is normal for your computer to restart continously after you installed the RAM. The thing that you did wrong was unplugging the battery while the computer was on. You didn’t make your computer faulty as a result of that. Reboot your computer, with the newly installed memory module, and do not touch anything and let it boot up and do that loop that you mentioned. If that turns out to not be a solution to your concern, please tell me more.

Hello cedarj, Your computer could be slow for many reasons. There may be one or more reasons why your computer is slow. 1) What OS is installed on your computer? (This HP Compaq DC5700 can only go up to Microsoft Windows 7 as the highest operating system that it support in terms of Microsoft Windows.) 2) How much RAM do you have installed on your computer? (Your RAM could be the reason why your computer is slow. You could have unnecessary processes running in the background of your computer while it is on without you even knowing about them and or your RAM itself is not exactly equip to handle the kinds of tasks that you are doing on your computer, in that case either upgrade your RAM, upgrade your hard drive to a solid state drive and or replace whatever operating system that you currently have installed on the computer to a more lightweight and manageable operating system such as Linux.) What kind of storage device is installed on the computer and how much is it? (Hard drive’s have moving parts inside of...

Have you checked the driver/drivers for the iFixit battery that you used to replace your faulty one with? It is probably a software issue.