Reinstall a WSP Package in Sharepoint 2010

Steps:
1. Retract
2. Delete Solution
3. Add Solution
4.Deploy Solution

1.Retract:
Go To Central Admin - System Settings - Manage Farm Solutions - Select and Retract the solution

2.Delete Solution:
Open PowerShell as Admin
Type
Remove-SPSolution –Identity YOUR_WSP_NAME.wsp

3.Add Solution:
Open 14 hive in cmd
C:\Program Files\Common Files\Microsoft Shared\Web Server Extensions\14
Run command:
stsadm.exe -o addsolution -filename D:\YOUR_WSP_NAME.wsp

4. Deploy Solution:
Go To Central Admin - System Settings - Manage Farm Solutions - Select and Deploy solution