I have had this issue and think I've found the solution - if you open the file in wordpad and remove any lines relating to queries (examples below) then that should speed up the opening of .wor files.
Examples of lines to remove:
Select * from Addr_Pt , National_Rail_Stations where Addr_Pt . obj within National_Rail_Stations . obj into Query3 noselect
Select * from Addr_Pt , National_Rail_Stations where Addr_Pt . obj within National_Rail_Stations . obj into Query4 noselect
Select * from Addr_Pt , National_Rail_Stations where Addr_Pt . obj within National_Rail_Stations . obj into Query8 noselect
Select * from Addr_Pt , National_Rail_Stations where Addr_Pt . Obj within National_Rail_Stations . Obj into Query1
Select * from Addr_Pt , National_Rail_Stations where Addr_Pt . Obj within National_Rail_Stations . Obj into Query2
Select * from Addr_Pt , National_Rail_Stations where Addr_Pt . Obj within National_Rail_Stations . Obj into Query5
These lines come straight after the table lines and before the map line
E.g:
!Workspace
!Version 950
!Charset WindowsLatin1
Open Table "\\solar\data_Library\Mapping\OS_Data\Landline\Water" As Water Interactive
Open Table "\\solar\data_Library\Mapping\OS_Data\Landline\Boundary" As Boundary Interactive
Open Table "\\solar\data_Library\Mapping\OS_Data\Landline\Building" As Building Interactive
Open Table "\\solar\data_Library\Mapping\OS_Data\Landline\Centreline" As Centreline Interactive
Open Table "\\solar\data_Library\Mapping\OS_Data\Landline\Fence" As Fence Interactive
Open Table "\\solar\data_Library\Mapping\OS_Data\Landline\General" As General Interactive
Open Table "\\solar\data_Library\Mapping\OS_Data\Landline\Names" As Names Interactive
Open Table "\\solar\data_Library\Mapping\OS_Data\Landline\Rail" As Rail Interactive
Open Table "\\solar\data_Library\Mapping\OS_Data\Landline\Road" As Road Interactive
Open Table "R:\12 Library\GIS library\Projects\Overground\LOCIP\National_Rail_Stations" As National_Rail_Stations Interactive
Open Table "\\solar\data_Library\Mapping\OS_Data\AddressPoint\SE_England_tiles\TQ2504_3499\Addr_Pt" As Addr_Pt Interactive
Open Table "R:\12 Library\GIS library\Layers\London Overground Stations" As London_Overground_Stations Interactive
**Select * from Addr_Pt , National_Rail_Stations where Addr_Pt . obj within National_Rail_Stations . obj into Query3 noselect
Select * from Addr_Pt , National_Rail_Stations where Addr_Pt . obj within National_Rail_Stations . obj into Query4 noselect
Select * from Addr_Pt , National_Rail_Stations where Addr_Pt . obj within National_Rail_Stations . obj into Query8 noselect
Select * from Addr_Pt , National_Rail_Stations where Addr_Pt . Obj within National_Rail_Stations . Obj into Query1
Select * from Addr_Pt , National_Rail_Stations where Addr_Pt . Obj within National_Rail_Stations . Obj into Query2
Select * from Addr_Pt , National_Rail_Stations where Addr_Pt . Obj within National_Rail_Stations . Obj into Query5**
Map From London_Overground_Stations,Addr_Pt,National_Rail_Stations,Names,Road,
Rail,General,Fence,Centreline,Building,Boundary,Water
Position (0.0520833,0.0520833) Units "in"
Width 4.52083 Units "in" Height 4.58333 Units "in"
Set Window FrontWindow() ScrollBars Off Autoscroll On Enhanced On Smooth Image High
Set Map
Hope that helps!