Windows 7 - Memory usage way too high- hovering aroung 50%

Hey all, I've been noticing for the last few days that my memory usage is very high.
I am using an HP 635 and I keep noticing my memory usage is excessive; hovering around 50% or so. It even got to the point of causing a BSOD today.
I have tried disabling all plugins and extensions on Firefox and closing it, but that did little good. Please tell me how to fix this!
Also, if you need more info or need me to do something, please keep in mind that I can be very tech illiterate at times (know some things, have no idea about others) so use small words and all that jazz. Thank you very much!

What makes you think it is "high"?

What makes you think memory usage is the cause of your BSODs?

"hovering around 50%" of what?

This is just high in my subjective experience. I am using 50% if my memory, according to task manager, and that seems too high for comfort.
I know the memory was the cause of the BSOD because the error name was MEMORY_MANAGEMENT (caps are theirs, not mine.)

I think he meant what does 50% mean in gigs? How much ram do you have installed? 50% of 2 gig would be normal, 50% of 4 gig /may/ be a little high. 50% of 8 gig on boot would definitely be too high for a stock install...

I have two gigs. I just worry because this is A. My school laptop (I take all online classes) and B. The computer where I write all my stories (I am an amateur author) so I just want to take good care of it. I'll just keep an eye on things I guess and start looking at things if it gets to 60% or more.
Thanks!

Sounds fine to me.

Look at the memory tab of performance monitor to keep track.

I have 4 gigs and normally use 1.5 or so.

With only 2 GBs you cannot expect any less. My systam uses 1.9GB (of 8GB) right now. The /7 system is very good at managing RAM. And there is no need to save RAM for a rainy day.