ctrader desk top freezing...

Recently,

I often experience disconnection or freezing while memory rise over 50%.

broker :fxpro.

my desktop pc spec.

Processor
Model : Pentium(R) Dual-Core  CPU      E5200  @ 2.50GHz
Speed : 2.5GHz
Cores per Processor : 2 Unit(s)
Threads per Core : 1 Unit(s)
Type : Dual-Core
Integrated Data Cache : 2x 32kB, Synchronous, Write-Thru, 8-way, 64 byte line size
L2 On-board Cache : 2MB, ECC, Synchronous, ATC, 8-way, 64 byte line size, 2 threads sharing

Computer
Mainboard : Gigabyte EP31-DS3L
BIOS : Award (Phoenix) FDa 10/27/2008
Bus(es) : X-Bus PCI PCIe IMB USB i2c/SMBus
Multi-Processor (MP) Support : No
Multi-Processor Advanced PIC (APIC) : Yes
Total Memory : 2GB DIMM DDR2

Chipset
Model : Giga-Byte P35/G33/G31 Processor to I/O Controller
Front Side Bus Speed : 4x 200MHz (800MHz)
Total Memory : 2GB DIMM DDR2
Memory Bus Speed : 2x 400MHz (800MHz)

Memory Module(s)
Memory Module : Samsung M3 78T2863RZS-CF7 1GB DIMM DDR2 PC2-6400U DDR2-800 (5-6-6-18 3-24-6-3) *3 (total 3GB)

Video System
Video Adapter : NVIDIA GeForce 9500 GT (32 SP 1.4GHz, 512MB DDR2 2x400MHz, PCIe 1.00 x16)
Video Adapter : NVIDIA GeForce 9500 GT (32 SP 1.4GHz, 512MB DDR2 2x400MHz, PCIe 1.00 x16)

Graphics Processor

Storage Devices
WDC WD3200AAKS-00L9A0 (320GB, SATA300, 3.5", 7200rpm, NCQ, 16MB Cache) : 298GB (C:) (D:)
TSSTcorp CDDVDW SH-S223Q (SATA150, DVD+-RW, CD-RW, 2MB Cache) : N/A (E:)

Logical Storage Devices
Hard Disk (C:) : 156GB (NTFS) @ WDC WD3200AAKS-00L9A0 (320GB, SATA300, 3.5", 7200rpm, NCQ, 16MB Cache)
Hard Disk (D:) : 142GB (NTFS) @ WDC WD3200AAKS-00L9A0 (320GB, SATA300, 3.5", 7200rpm, NCQ, 16MB Cache)