I would ttroubleshoot this by disabling the 'New' menu entries (except for perhaps Folder and Shortcut). If the menu then functions & doesn't crash Explorer, you can re-enable the items one-by-one until you find the misbehaving one.
A 'New' context menu item appears if the associated file extension has a subkey named 'ShellNew' in the Registry. So open regedit.exe, Ctrl+F (search), type 'ShellNew' and make sure you are searching for keys:
The first one found will most likely be under .bmp. When found, right-click the key, select Rename, and prefix with an 'x' (renaming is sufficient to disable):
Ctrl+F3 will repeat the search, rename all entries except for .lnk and Folder, restart Explorer or log off & back on for the changes to take effect, then test the behavior.
Keith