Hi Hacky. A search in Google for the phrase "disk has restarted due to other programs writing in the background" shows that yours is not an unusual problem, and can be caused, among other things, by bad sectors on the hard drive, trojans or viruses click here.
A suggestion I found was to run Scan Disk from DOS. click here, and the following is copied from that site:
1. Click on start, shut down, and restart in MS-DOS mode.
2. Now type CD\. and then press Enter on the keyboard.
3. You will be at the dos prompt now: C:
4. Type SCANDISK, and press Enter.
5. This will start the process, and when it gets all the way through the numbers, and asked if you want to do the full surface scan, choose yes with your arrow keys, and press Enter on the keyboard. This will take a while, hours for most. Best to run this at night so it doesn't interfere with your daily computing. Just turn off the monitor, and walk away. In the morning, you can read the results, and then exit the program, and when you see your dos prompt again, C:\, then turn off your computer, and restart it.