Ok, well even after reformatting the problem is still occurring. So ill be playing R6: Vegas and it will show in the processes list that the game is taking up 450mb of RAM and lets say probably everything else is taking about 100mb so thats about 550mb of RAM being used, but when i go to the 'performance' tab in task manager it will say that there is only 50mb of RAM available. It should say that there is about 450mb available, shouldn't it? And the reading of how much is available is not wrong, because i am getting huge lag spikes that happen. This same problem is also occuring when i try to run BF2. It will be saying that its taking about 600mb then there will be only 70mb of RAM available. What could be causing this?

How much RAM do you have? Please post all of your system specs so we can help you further. (include the OS as well).

Although not directly stated, the OP implied that he has 1 GB of actual RAM... he says 450 MB for the game, 100 MB for Windows and based on his math that means that there should be 450 MB left... 450 + 100 + 450 = 1000.

BF2 gave me fits with 1 GB of RAM... especially if you've got the expansion(s) I've got a screenshot of BF2.exe using right at a full gigabyte of RAM by itself... so on a 1 GB system, that game will be forced to rely on the hard drive.

I'm still curious why you're showing so little free... are you sure your computer is properly recognizing the full amount of memory you have?

How many sticks of RAM do you have and what are they're capacities?

If you running something like [4x256mb] or [1x512mb, 2x256mb], you could be experiencing faulty hardware.

You said you had 450mb running R6 Vegas, about 100mb running Windows and 50mb of free memory. Now considering that RAM usually keeps space free for transfer purposes, you may only be running at 768mb.

Also, later on you say your computer is using 600mb with 70mb free.

So as Rodney said earlier check to see how much RAM your OS is recognizing. It should be somewhere near 1024mb if thats what you think you have.

Sry about that, i forgot to post my specs.
AMD64 3200+ 2.0Ghz
1GB (2x512) DDR400
Evga 7600GTS
80GB Hitachi HD
Windows XP pro SP2

My O/S and any other 3rd party program shows that i have the full 1024mb of RAM. Also, for R6:Vegas, my friend with 512mb (2x256)(P4 3.4Ghz,6600GT) is able to run the game better than me when the min requirement is 1GB. btw, im running R6: Vegas

For BF2 ive heard of many people being able to run the game at higher settings than me with 1Gb of RAM.

Does the lag only happen with those 2 games?
When you play, do you hear your hard drive grinding away? If yes, then I'd give memtest86 a shot and see if anything pops up there.

Also, make sure your Task Manager is showing you all the processes from all the users.

Double check the Advanced settings tab on the Performance Options in the System Properties window? (Throwing ideas out here)