contain(s) remnants of word processing documents, e-mails, Internet browsing activity, database entries, and almost any other work that has occurred during past Windows sessions.

Swap files contain(s) remnants of word processing documents, e-mails, Internet browsing activity, database entries, and almost any other work that has occurred during past Windows sessions.

Explanation:

I order to simulate extra space an operating system like windows use hard disk space in order to stimulate extra memory.When a computer system is running low with the memory space the swap file swaps a section of RAM onto the hard disk in order to obtain a free memory space.

This Process at times results in  slowing down of the computer  computer considerably.

The combination of RAM and swap files is known as virtual memory.

It is due to the  use of virtual memory that our computer is able to  run more programs than it could run in RAM alone.