Linpus seems to be a "dormant" distro,
according to DistroWatch. Even the English language version of the
Linpus Website has not been updated in about 3 years. Few people here, if anyone, is going to have any experience with that system.
So, that means you are going to have to try different things to see what works for you. My first suggestion already was to try to boot on UEFI-ready Linux distros, such as Linux Mint or Ubuntu. They may install easily, but they may not.
If you think you have to put the BIOS into Legacy mode, some systems need you to create a BIOS password first before they will allow you to make that change. But that may or may not be true for your computer. Some Linux distros will require Legacy mode to install, but I would try the UEFI-ready ones first.
Sometimes, in rather rare cases, some systems are very hard-wired to run only what they were sold with.... and in the worst case, that could be true for you because it seems you bought something designed for a very limited market.
And maybe others here will have better advice for you than me.