Yes, it's in Parallels Tools folder. XPDM driver installation instructions are below just in case.
But can you describe more specifically what problems you're having with which applications? It would also be usefull to know what Mac you're running on and OS X version too.
This is how to install XP video driver in Vista/7:
• Click Run in Windows Start menu, type in devmgmt.msc and click OK.
• In the device manager expand Display Adapters, right-click on Parallels Display Adapter and choose Update Driver Software
• Click Browse my computer for driver software
• Click Let me pick from a list of device drivers on my computer
• Click Have Disk and browse to C:\Program Files (x86)\Parallels\Parallels Tools\Drivers\prl_va
• Click Next
• If Windows asks for confirmation select Install this driver software anyway
To revert back to WDDM driver later follow the same steps but select C:\Program Files (x86)\Parallels\Parallels Tools\Drivers\prl_dd as driver path.
If anything goes wrong you can always uninstall/reinstall Parallels Tools and the driver will return to WDDM.