How to upgrade 32 bit with 1 GB RAM PC to 64 bit and can I install 4 GB RAM

This is an interesting question.
It is possible that your computer is capable of running a 64-bit operating system but has a 32 bit OS installed on it currently. To check this, please follow these steps:

1. Press Windows key + I
2. Select System
3. Click on About your PC
4. Look for System Type. Here it will be mentioned what bit your OS is and what bit your processor is. If it says x64-based processor, then you just need to reimage your PC with a new 64-bit OS. However, if it says x86-based processor, then you can't install a 64-bit OS on it since this is decided by the processor which is part of the motherboard. Replacing the motherboard is as good as buying a new laptop.

As for your query on RAM, it needs to be checked from the specifications list. Since you haven't mentioned your laptop brand and version, I can't tell you directly. But just like smartphones, the specifications list will mention how much you can extend your laptop RAM. If you have 1 GB of RAM currently, it might be possible to expand it to 2 GB but 4 GB is doubtful. Again, if you can mention the brand and version of your laptop, I can give you an exact answer.

If you have a 32-bit processor, I would suggest disposing of this laptop and buying a new one.

So you have two questions here. One being migrating from 32 bit to 64 bit OS. So let me answer them separately.

1) If you have 32 bit OS and wish to upgrade your OS to 64 bit OS then you should not go through the upgrade process for OS through DVD disc. You should be making the clean format the machine and install the 64 bit OS. For example 32 bit OS apps don't properly get moved to the 64 bit and there are many people who faced the issues. This is true especially in context of updates. So from that angle, you should consider clean install. If you are in doubt about this 32 bit to 64 bit OS, you should consider clean install. My suggestion: Go for clean install of 64 bit OS.

2) Second question, you may add the RAM 4 GB regardless of your OS being 32 bit or the 64 bit. In case of the system lag and other slow computer process, you may notice difference when you upgrade to 4 GB. So I'd recommend you to upgrade the RAM if possible.

For upgrade OS from 32Bit to 64Bit in your laptop, you need to install the 64Bit version of your OS. Whether you use license copy of OS in your laptop, it is conveniently accessible on the Microsoft website. There is no other way to do live 32Bit to 64Bit upgrades for operating system. Formatting and re-installation is the only option.