Aero not working in WIndows 7 Ultimate on PD4

Hello Folks

I have been trying to make Aero work on Windows 7 Ultimate (64 bit) on Parallels Desktop Build 4.0.3848.
Despite having a strong configuration, the Windows Performance Index shows the following giving me a score of 1.0 in Gaming Graphics.

I checked Device Manager and the display Adapter is "Parallels Video Adapter". I did some research and it does not show WDDM which i guess it should show. Did all the possible updates including installing the drivers again but still no luck My Video memory is 256 mb in total out of which 128mb is used by Virtual Machine. Graphics card is ATI Radeon HD2400 (256 Mb)

More details about my computer


Component Details Subscore Base score
Processor Intel(R) Core(TM)2 Duo CPU T7300 @ 2.00GHz 4.9 1.0
Determined by lowest subscore

Memory (RAM) 2.00 GB 4.9
Graphics 1.9
Gaming graphics Not detected 1.0
Primary hard disk 13GB Free (32GB Total) 5.9
Windows 7 Ultimate

System
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Manufacturer Parallels Software International Inc.
Model Parallels Virtual Platform
Total amount of system memory 2.00 GB RAM
System type 64-bit operating system
Number of processor cores 2

Storage
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Total size of hard disk(s) 32 GB
Disk partition (C 13 GB Free (32 GB Total)
Media drive (D CD/DVD

Graphics
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Total available graphics memory Not detected
Dedicated graphics memory 0 MB
Dedicated system memory 0 MB
Shared system memory 0 MB
Display adapter driver version 4.0.3854.56988
Primary monitor resolution 1355x788
DirectX version DirectX 9.0 or better

Network
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Network Adapter Parallels Ethernet Adapter




Has anyone faced this problem before. Please help me out folks. Any help would be appreciated. will this problem solved if i upgrade to parallels 5.0

Thanks a lot in Advance.