For those new to computing here are two tips to maybe help you understand why system memory may lie or trouble you.

1. 32-bit operating system will only see anywhere from 3Gb to 3.5 of system memory. Alot depends on the memory, and motherboard. My personal computer will only recognize 3.5 Gb but I run 6 Gb in my system. I also run Vista 64-bit OS and then my computer will see all the memory I have. I run 2 versions of Win Vista both the 32-bit and 64-bit on a partitioned drive, it allows me to compare and take advantage of more memory. What I am getting at is don't let a salesman try and sell you 6 or 8 Gb of memory if all your running is Vista 32-bit.

2. We have had some problems with OS freeze or restart (during the nite, strange how this happens) and then have had problems re-booting or recovering from this. So we never let our computer go into sleep mode and this has helped us, and our customers. So to set this setting right click on the desktop and personalize settins, click screen saver and then, power options and on the left change when computer sleeps. Use the dropdown menu from put computer to sleep and change to never. This may help solve some re-boot problems you may have.

3. Watch out for problems with the virus protection you may have like McAfee because it somtimes mistakes some of your system files for a virus. At Business Processes Inc. we have good luck with the free version of avast, but just be careful because without SP1 for Vista the OS is somewhat virus program unfriendly. Here is the like for Avast home edition.
http://www.avast.com/eng/download-avast-home.html