Try this approach.
1, Right click on Tally icon and Run as administrator
2, If that didn't work then Right click Troubleshoot Compatiblity and follow the wizard
1. Is tally 7.2 compatible with win7?
2. Have you gone to tally.com and did a search for updated driver's or do a search there for problems by others similar to yours?
3. Do you have any AV or firewalls blocking the install?