I've had a weird problem lately when booting Windows 7 Ultimate:
- If I restart the PC, Windows 7 boots as usual.
- If I shut the PC down and start it up I get a "Missing operating system" error. If I then restart with Windows 7 installation disk and quit the installation with "Restart", Windows boots normally. The same applies with the Ubuntu 11 installation disk.
I've noticed that this is my disk set up:

On my other PC the "Unallocated" partition is called "System Reserved" with a status of (Active, System). Could that be related to this problem?
I've tried System Repair with F8 but this didn't change anything. I've had the PC for over a year now and this problem only started around a week ago.