System is shutting down quite often

Attachment 117669I am experiencing problem with my Acer Aspire Laptop. System is getting hot very quickly and shutting down. It's happens when I browse Internet and plays the NFS Most Wanted Game. Please advise how can I resolve this problem.
I have tried upgrading BIOS version also tried running Combo fix. Please find the attached log file.
While running the COMBOFIX system went off automatically.
System Info:
Operating System: Windows Vista™ Home Premium (6.0, Build 6002) Service Pack 2 (6002.vistasp2_gdr.120824-0336)
Language: English (Regional Setting: English)
System Manufacturer: Acer
System Model: Aspire 4730Z
BIOS: InsydeH2O Version V1.22
Processor: Intel(R) Pentium(R) Dual CPU T3200 @ 2.00GHz (2 CPUs), ~2.0GHz
Memory: 1978MB RAM
Page File: 1354MB used, 1365MB available
Windows Dir: C:\Windows
DirectX Version: DirectX 11
DX Setup Parameters: Not found
DxDiag Version: 7.00.6002.18107 32bit Unicode

Regards,
Suman

Attached Files

	ComboFix.txt (19.4 KB)
	Hight CPU Utilization.doc (1.10 MB)
	System Health Report Oct12.txt (790.2 KB)