SQL Express 2005 - Primary File Group Full - Attempts to Drop indexes or Delete data fail.....

I have a database that is at the maximum size for SQL 2005 Express edition of 4Gb.

When I try to run the following statement, I get the errors below:
USE SPCTR_DV GO IF  EXISTS (SELECT * FROM sys.indexes WHERE object_id = OBJECT_ID(N'[dbo].[tblEmailAttachments]') AND name = N'idx_Clustered') DROP INDEX [idx_Clustered] ON [dbo].[tblEmailAttachments] GO IF  EXISTS (SELECT * FROM sys.indexes WHERE object_id = OBJECT_ID(N'[dbo].[tblEmailRecipients]') AND name = N'idx_Clustered') DROP INDEX [idx_Clustered] ON [dbo].[tblEmailRecipients] GO IF  EXISTS (SELECT * FROM sys.indexes WHERE object_id = OBJECT_ID(N'[dbo].[tblEmailTrans]') AND name = N'idx_Clustered') DROP INDEX [idx_Clustered] ON [dbo].[tblEmailTrans] GO
Errors:
Msg 1101, Level 17, State 2, Server CS360\SPECTOR360, Line 2 Could not allocate a new page for database 'SPCTR_DV' because of insufficient disk space i ...