Tool to show processes writing to the hard drive?

ProcMon from Sysinternals/Microsoft.

You're aware Task maanger can have columns for

• I/O Reads
• I/O Read bytes
• I/O Writes
• I/O Write bytes
• I/O Other
• I/O Other bytes

? That might help - see View/Select Columns

Process Explorer from Microsoft SysInternals. You can view this info about all processes at once, or get even more detailed information when you double-click on a single process.

This is one of those tools I can't live without.

_{(source: microsoft.com)}

_{(source: microsoft.com)}