The QuickTest Asset Upgrade Tool for Quality Center enables you to simultaneously upgrade all of the QuickTest assets from an earlier QuickTest version to version 10.00 format. This applies only to QuickTest assets stored in a Quality Center 10.00 project.

You can find this tool in your QTP installation DVD and also you may download it from following link; 

AssetUpgradeToolForQC.rar (1,07 mb)

QuickTest assets include:
- Testing documents, such as tests, actions, components, and application areas.
- Attachments that are associated with tests, actions, components, and application areas, such as function libraries, shared object repositories, data table files, environment variable files, and recovery scenario files.

In addition to upgrading your QuickTest assets to the current version of QuickTest, the QuickTest Asset Upgrade Tool for Quality Center converts these testing assets from attachments to linked entities that use the new Resources and Dependencies model. All converted resource assets are copied from their attachment location in the Test Plan module to the Test Resources model.

Consider that sometimes updating process takes so long if your QC project has a lot of QTP assets ( > 50K) . 

Cheers, 

Okan