The beep code is pretty accurate - I've never known it to be wrong - But just like everyting dealing with computers, it is not 100% certain.
What I think is happening here is your memory is probably bad, but your replacement memory is not compatible with your HP. So it
appears to be a problem other than memory, but in all likelyhood is.
Just because you switch the RAM with "known good RAM", it does not necessarily mean it will work. Computers are SO picky, there are many variables to be accounted for. This is VERY true for HP systems. There's been plenty of times I've tried good quality, name-brand memory and it hasn't worked properly in HP, Gateway or Compaq computers.
The things you need to take in account with your replacement memory is that it meets the following requirements to work on your system:
1.) PC-100Mhz
2.) Must NOT be double density! Many newer memories (especially larger modules) are DD. These will often not work in "older" systems such as yours. You may be able to check your replacement memory's compatibility with your system by looking up the model number of the memory and your computer on
www.google.com .
3.) Name brands are highly recommended. Generic memory has poor compatibility and HP/Compaq ESPECIALLY have a hard time accepting 3rd party memory.
If memory is not to blame here, it means your motherboard is damaged in some way (DIMMs are bad, for example). This is very unlikely unless you physically damaged your board somehow.
There's also that very small chance the error beep is bad or perhaps you are misinterpreting the beeps.