My Computer has got 2GB installed RAM, nut when I check in the the system properties, it shows that only 1.89GB is usable. Help me free RAM?

Check Installed Ram

If you have integrated video, then a portion of your system RAM is allocated as a frame buffer for the integrated GPU. if you've got 128MB of system RAM being allocated, then having 1.89GB out of 2GB free sounds about right.

A certain amount of RAM is always used by system processes. I don't think it's possible to free up more RAM, 1.89GB is a good result in your particular case.

The operating system is using it and you cannot free up any more. RAM is very easy to install and some RAM is very cheap.

The amount being used from the 2GB is from your video card. There's no way to "free" the RAM. Your generic video card shares it with the system motherboard.

this is normal...

that 2gb rating is in metric. computers dont use metric they use base 2 (2 gb is about 2,000,000 in metric, but a computer uses base 2 1,048,576)

I suggest junking the dinosaur and getting one with at least 4GB. New ones are really cheap.