Cubase 12 crashes -

Cubase 12 crashes every 5 minutes. Will I need to buy a new computer?
Cubase 11 works correctly.

Hi and welcome to the forum,

This is an English language forum.

If you have a crash, describe the last steps before the crash and attach the *.dmp/ips file, please.

Mac: macOS Console utility > Crash Reports (or ~user/Library/Logs/Diagnostic Reports).
Win: Documents/Steinberg/Crash Dumps

for me , after several years, it is almost always a plugin that causes it. Disable them all or some or one you might have loaded of late. Narrow it down and you might find out it is a plugin.
Other than that, the program might have become corrupted and a re-install can help, even if you just installed it.