Zestou,
I've received your PM but I thought You and anyone with a similar issue will find it beneficial and helpful.
If the S340 chassis doesn't have the reset connectors then I think you can;
a| contact the case manufacturer, NZXT, or the people who you bought the chassis from and notify them of the issue
b| you won't require a reset button since most hardware won't be causing an issue we one used to see back on Windows 98 and XP
As per your PSU - remove and replace
immediately. In order to figure out if the existing hardware is working you'd need a donor PSU and connect it to your system to check it out. If not then you're flying blind. If the components don't fire up with a donor/new PSU - then you've lost them to that generic unit
🙁