A few things to try:
1) Start -> Run -> services.msc -> Disable "Superfetch". I've had it bug out and cause this, I just disable it now on fast systems.
2) Start -> Run -> Prefetch -> Delete everything.
3) Set page file to 1024-1024 on your Raid 0 partition, disable any others. Do not set it to 1024-2048 you want a static number.
5) See if it's fixed.
-> Do not disable the page file. It sickens me that people still suggest that.
-> Windows is not actually using 2GB of RAM. It's probably using about 700MB with 1.3GB cached. It will release that RAM whenever you need it. Your RAM usage is normal.
@OP ^ Excellent recommendations.