Vista only recognizing 2.4G of 4G RAM?

Ok, I have 2-2G Sticks of RAM installed. I recently Updated my Beta Preferences for Blizzard. The program that records all the information said that there was only 2.4G of RAM? Where is the other 1.6G?

Im running Windows Vista 64bit, not sure on what SP tho

I keep trying to Render videos with Sony Vegas Pro 9.0 and it wont let me error keeps popping up saying "Your system is low on memory.Yo may be able to lower memory usage by closing other application." When I bring up my Task Manager, Sony vegas is the only thing running that is using alot of memory, then next thing under it is Windows Explorer at 30,000K?


Help plz?

 

Under System in your control, what does that read for memory and SP?

If this started with the upgrade, can you uninstall same upgrade? Uninstall the whole thing?

Then I would download and run cCleaner from Here

Failing any of this, can you do a system restore to a point before the problems?

To rule out memory board problems, try running memtest;

http://majorgeeks.com/MemTest_d350.html

Let it run at least an hour.

 

Running a diagnostic as suggested by brandypeppy is definitely a good idea, but you could check the PC BIOS real quick to see what is reported there. Most PCs use either Del, F1, F2, or F10 to enter the BIOS. Press the required key right when you first power on to enter the BIOS (also known as "Setup"). You will probably have a message on-screen right when you power up that says "<DEL> for Setup" or maybe "Press F2 for BIOS" or something similar..... there should be a spot in there that shows how much memory is installed....

 

Under System it says SP2 and 4G of RAM. Dont know exactly when it started only realized that the program only recognized that 2.4G of ram was there yesterday. Ive only started getting the "Not enough memory" errors about a week now tho. IAnd under the Task manager when im rendering it says Memory Usage and its between 50-75%.

 

IAnd under the Task manager when im rendering it says Memory Usage and its between 50-75%.

What is rendering?

Under task manager, under the performance tab, with other Windows closed, no scans running, CPU usage should be 0 to maybe 5%, but mine always says 0, due to my setup. And yours?