They may be able to answer your questions in better detail. As for info about your mainboard, open the Search box and type 'system info' and select the option offered. Alternatively, you can download a diagnostics app, e.g. HWINFO - it's freeware, and you'll get lots of info. You'll also get detailed info about your CPU.
But I have to agree with the other posters - replacing your mainboard, no matter the brand, is going to be a major operation, and at best you'll only be able to install the exact same board.
I searched for HCL laptops but could only find listings that were consistently Out of stock or Discontinued - and that's never a good sign.
I have a car nobody has heard about, but it is underpowered, only 50hp (which was great twenty years ago). I want to replace the engine, transmission, and differential so I can get more powerful car. Where I can buy parts?
You're best off buying a new laptop. You can upgrade the RAM if that's possible, replace the hard drive with an SSD drive for more performance. Some laptops have socketed processors, so an upgrade to a better one IS possible, but you need to know what motherboard is in there, make, model, processor, chipset, etc. Download CPU-Z and run it. It will tell you what you have and you can go from there. Some newer laptops have sealed cases that can't be easily opened, and the processors are soldered to the mainboard and can't be removed. So, be warned.... it's not recommended to open your laptop an monkey with it. You can end up breaking crap inside.