Memory Issues when opening Multiple files in Excel (VBA)

[OzzieOwl]

I am opening a series of files from a predefined list of files (could be around 200), I am opening the files one at a time, then copying and pasting some information across to the current worksheet, then I close the donor file down, and repaeat the process with the next file.
My PC keeps hanging after about 15 files, it seems that the memory gets full up. Does anyone know how to close files and clear any trace of them from the memory.
Any help greatly appreciated.

Martin