Question No post beep after RAM upgrade

May 26, 2019
Last time I've decided to upgrade my old computer's RAM. Before my upgrade it had 512MB RAM (2x256MB Goodram GR400D64L3/256)
I've bought 2x1GB Kingston's KVR400X64C3A/1G and installed It into my PC.
First time I've powered it on It was working like It should.
The second time I've powered it on It started to work very loud, there wasn't any post beep or image on my display.
Once I left it untouched for 3 days. After that time I've powered it on, and It was working 100% ok.
However turning it off and turning it on made the problem again.
I'm not sure if RAM I've got is damaged, but it was packed pretty well.
After removing new RAM and installing the old one, PC was working like before the upgrade.

PC specs:
CPU: AMD Athlon 64 3000+ 1,8GHz
Motherboard: Gigabyte GA-K8NF-9
GPU: nVidia GeForce 9400 GT 512MB
PSU: Chieftec 350W
OS: Windows 7 Ultimate x86

Some ideas why is that happening? Any help will really be appreciated.