Asus HD 5450 Silent 1GB DDR3 video card problem

I just bough a ausu hd 5450 silent 1gb ddr3 graphics card on the 24th of this month december.. i installed the card and installed the drivers on the cd.. restarted computer and then disaster..went to the website to install the latest drives and the same thing happens.. when browsing on the net everything is super slow and choppy.. i have the latest shockwave flash and i made sure i installed the right drivers for the graphics card and even installed back drivers (later date drivers).. even when im off the net when i go to the start button it comes up weird and not smooth and normal... also i dont know if this helps but one thing i did notice is when im on a webpage that doesnt have graphics the page loads up and scrolls smooth but when it has graphics like this forum it messes up.. does anybody have any suggestions as in why this is happening? thanks soooo much!!

heres my info below

Operating System System Model
Windows XP Professional Service Pack 3 (build 2600)
Install Language: English (United States)
System Locale: Croatian
Installed: 4/16/2011 11:04:16 AM
Boot Mode: Legacy BIOS in UEFI (Secure Boot not supported) Enclosure Type: Desktop
Processor a Main Circuit Board b
3.50 gigahertz AMD FX-6300 Six-Core
288 kilobyte primary memory cache
6144 kilobyte secondary memory cache
8192 kilobyte tertiary memory cache
64-bit ready
Multi-core (6 total)
Not hyper-threaded Board: 970A-G43 (MS-7693) 3.0
Bus Clock: 200 megahertz
UEFI: American Megatrends Inc. V10.2 02/04/2013
Drives Memory Modules c,d
570.11 Gigabytes Usable Hard Drive Capacity
34.63 Gigabytes Hard Drive Free Space

Memorex DVD+-RAM 530L v1 USB Device [Optical drive]

WDC WD2500AAJB-00J3A0 [Hard drive] (250.06 GB) -- drive 1, s/n WD-WCAV2P599403, rev 01.03E01, SMART Status: Healthy
WDC WD3200AAJB-00J3A0 [Hard drive] (320.07 GB) -- drive 0, s/n WD-WCAV2Z877839, rev 01.03E01, SMART Status: Healthy 3292 Megabytes Usable Installed Memory

Slot 'A1_DIMM0' is Empty
Slot 'A1_DIMM1' is Empty
Slot 'A1_DIMM2' has 4096 MB
Slot 'A1_DIMM3' is Empty
Local Drive Volumes

c: (NTFS on drive 0) * 320.06 GB 32.66 GB free
d: (NTFS on drive 1) 250.05 GB 1.97 GB free


Microsoft XPS Document Writer on XPSPort:
Controllers Display
Primary IDE Channel [Controller] (2x)
Secondary IDE Channel [Controller] (2x)
Standard Dual Channel PCI IDE Controller (2x) ASUS EAH5450 Series [Display adapter]
AOC F19 [Monitor] (18.5"vis, s/n 18496, November 2008)
Bus Adapters Multimedia
NERO IMAGEDRIVE SCSI Controller
Renesas Electronics USB 3.0 Host Controller (2x)
Renesas Electronics USB 3.0 Root Hub (2x)
Standard Enhanced PCI to USB Host Controller (3x)
Standard OpenHCD USB Host Controller (4x)
VIA Rev 5 or later USB Universal Host Controller (2x)
VIA USB Enhanced Host Controller AMD High Definition Audio Device
Realtek High Definition Audio