I don't have Win8, but S-09807 covers this. Let us know if this works.
Restore the icon association for SolidWorks files using these steps:
1. Start Windows® Explorer.
2. From the menu, select Tools->Folder Options.
3. Activate the file types tab.
4. In the registered file types list, select the SLDPRT, SLDASM or SLDDRW extension as required.
5. Click advanced.
6. In the Edit File Type dialog, click Change Icon.
7. Click Browse and browse to the location where SolidWorks is installed.
8. Select the file SLDWORKS.EXE and click Open.
9. Select correct icon and click OK.
10. Click OK twice to close the Folder Options dialog.
Unfortunately Win8 has got rid of the 'file types' tab from this menu!
I think the problem is that the file types are all set to the same thing - 'SldWorks Application' instead of having them as 3 different types.
I have read online that MS have flattened the icons for different programs to be the same to save resources:
(see 2nd image & surrounding text).
Need someone with Win8 to respond. Did a little googling and it looks to be a mess now.
In Windows Explorer, right click on an SLDPRT file
1. Pick "Open With"->"Choose Default Program" or "Open with..."
2. Make sure "Use this app for all .SLDPRT files" is checked
3. Select "SolidWorks Launcher" (don't select SolidWorks 2013).
Repeat for .SLDASM and .SLDDRW files.
Great, thanks Vajrang - Problem solved!
Keep up the good work worked fine for me, had to refresh the explorer window to get it display correctly.
Also cured the problem of windows trying to open another instance of solidworks when double clicking a file in explorer.